diff --git a/Assets/GameMain/Scripts/Simulation.meta b/Assets/GameMain/Scripts/Simulation.meta
new file mode 100644
index 0000000..089d035
--- /dev/null
+++ b/Assets/GameMain/Scripts/Simulation.meta
@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: 7f519a6e4d7b4cb4ab5eabf95fb55e1b
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Assets/GameMain/Scripts/Simulation/EnemySimData.cs b/Assets/GameMain/Scripts/Simulation/EnemySimData.cs
new file mode 100644
index 0000000..165074b
--- /dev/null
+++ b/Assets/GameMain/Scripts/Simulation/EnemySimData.cs
@@ -0,0 +1,15 @@
+using UnityEngine;
+
+namespace Simulation
+{
+    public struct EnemySimData
+    {
+        public int EntityId;
+        public Vector3 Position;
+        public Vector3 Forward;
+        public float Speed;
+        public float AttackRange;
+        public int TargetType;
+        public int State;
+    }
+}
diff --git a/Assets/GameMain/Scripts/Simulation/EnemySimData.cs.meta b/Assets/GameMain/Scripts/Simulation/EnemySimData.cs.meta
new file mode 100644
index 0000000..448e55c
--- /dev/null
+++ b/Assets/GameMain/Scripts/Simulation/EnemySimData.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: ef2eea85685544189eef2d9f2cece080
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Assets/GameMain/Scripts/Simulation/EntityBinding.cs b/Assets/GameMain/Scripts/Simulation/EntityBinding.cs
new file mode 100644
index 0000000..836fb16
--- /dev/null
+++ b/Assets/GameMain/Scripts/Simulation/EntityBinding.cs
@@ -0,0 +1,80 @@
+using System.Collections.Generic;
+
+namespace Simulation
+{
+    public sealed class EntityBinding
+    {
+        private readonly Dictionary<int, int> _entityIdToSimulationIndex = new Dictionary<int, int>();
+        private readonly Dictionary<int, int> _simulationIndexToEntityId = new Dictionary<int, int>();
+
+        public int Count => _entityIdToSimulationIndex.Count;
+
+        public void Bind(int entityId, int simulationIndex)
+        {
+            if (_entityIdToSimulationIndex.TryGetValue(entityId, out int oldSimulationIndex))
+            {
+                _simulationIndexToEntityId.Remove(oldSimulationIndex);
+            }
+
+            if (_simulationIndexToEntityId.TryGetValue(simulationIndex, out int oldEntityId))
+            {
+                _entityIdToSimulationIndex.Remove(oldEntityId);
+            }
+
+            _entityIdToSimulationIndex[entityId] = simulationIndex;
+            _simulationIndexToEntityId[simulationIndex] = entityId;
+        }
+
+        public void RemapIndex(int entityId, int newSimulationIndex)
+        {
+            if (!_entityIdToSimulationIndex.TryGetValue(entityId, out int oldSimulationIndex))
+            {
+                return;
+            }
+
+            _simulationIndexToEntityId.Remove(oldSimulationIndex);
+            _entityIdToSimulationIndex[entityId] = newSimulationIndex;
+            _simulationIndexToEntityId[newSimulationIndex] = entityId;
+        }
+
+        public bool TryGetSimulationIndex(int entityId, out int simulationIndex)
+        {
+            return _entityIdToSimulationIndex.TryGetValue(entityId, out simulationIndex);
+        }
+
+        public bool TryGetEntityId(int simulationIndex, out int entityId)
+        {
+            return _simulationIndexToEntityId.TryGetValue(simulationIndex, out entityId);
+        }
+
+        public bool UnbindByEntityId(int entityId)
+        {
+            if (!_entityIdToSimulationIndex.TryGetValue(entityId, out int simulationIndex))
+            {
+                return false;
+            }
+
+            _entityIdToSimulationIndex.Remove(entityId);
+            _simulationIndexToEntityId.Remove(simulationIndex);
+            return true;
+        }
+
+        public bool UnbindBySimulationIndex(int simulationIndex)
+        {
+            if (!_simulationIndexToEntityId.TryGetValue(simulationIndex, out int entityId))
+            {
+                return false;
+            }
+
+            _simulationIndexToEntityId.Remove(simulationIndex);
+            _entityIdToSimulationIndex.Remove(entityId);
+            return true;
+        }
+
+        public void Clear()
+        {
+            _entityIdToSimulationIndex.Clear();
+            _simulationIndexToEntityId.Clear();
+        }
+    }
+}
diff --git a/Assets/GameMain/Scripts/Simulation/EntityBinding.cs.meta b/Assets/GameMain/Scripts/Simulation/EntityBinding.cs.meta
new file mode 100644
index 0000000..b3aafca
--- /dev/null
+++ b/Assets/GameMain/Scripts/Simulation/EntityBinding.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: c4f6d93561db4b9092ab61182f2983d7
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Assets/GameMain/Scripts/Simulation/PickupSimData.cs b/Assets/GameMain/Scripts/Simulation/PickupSimData.cs
new file mode 100644
index 0000000..61dbf77
--- /dev/null
+++ b/Assets/GameMain/Scripts/Simulation/PickupSimData.cs
@@ -0,0 +1,12 @@
+using UnityEngine;
+
+namespace Simulation
+{
+    public struct PickupSimData
+    {
+        public int EntityId;
+        public Vector3 Position;
+        public float PickupRadius;
+        public int State;
+    }
+}
diff --git a/Assets/GameMain/Scripts/Simulation/PickupSimData.cs.meta b/Assets/GameMain/Scripts/Simulation/PickupSimData.cs.meta
new file mode 100644
index 0000000..695d645
--- /dev/null
+++ b/Assets/GameMain/Scripts/Simulation/PickupSimData.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: ff6e8b75e4af4c3ca9e3b732b1383f95
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Assets/GameMain/Scripts/Simulation/ProjectileSimData.cs b/Assets/GameMain/Scripts/Simulation/ProjectileSimData.cs
new file mode 100644
index 0000000..fa23db6
--- /dev/null
+++ b/Assets/GameMain/Scripts/Simulation/ProjectileSimData.cs
@@ -0,0 +1,15 @@
+using UnityEngine;
+
+namespace Simulation
+{
+    public struct ProjectileSimData
+    {
+        public int EntityId;
+        public int OwnerEntityId;
+        public Vector3 Position;
+        public Vector3 Forward;
+        public float Speed;
+        public float RemainingLifetime;
+        public int State;
+    }
+}
diff --git a/Assets/GameMain/Scripts/Simulation/ProjectileSimData.cs.meta b/Assets/GameMain/Scripts/Simulation/ProjectileSimData.cs.meta
new file mode 100644
index 0000000..54e9a43
--- /dev/null
+++ b/Assets/GameMain/Scripts/Simulation/ProjectileSimData.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 2eec1f4389004d69bdce8c4dd95d255e
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Assets/GameMain/Scripts/Simulation/SimulationTickContext.cs b/Assets/GameMain/Scripts/Simulation/SimulationTickContext.cs
new file mode 100644
index 0000000..2428dcd
--- /dev/null
+++ b/Assets/GameMain/Scripts/Simulation/SimulationTickContext.cs
@@ -0,0 +1,18 @@
+using UnityEngine;
+
+namespace Simulation
+{
+    public readonly struct SimulationTickContext
+    {
+        public SimulationTickContext(float deltaTime, float realDeltaTime, Vector3 playerPosition)
+        {
+            DeltaTime = deltaTime;
+            RealDeltaTime = realDeltaTime;
+            PlayerPosition = playerPosition;
+        }
+
+        public float DeltaTime { get; }
+        public float RealDeltaTime { get; }
+        public Vector3 PlayerPosition { get; }
+    }
+}
diff --git a/Assets/GameMain/Scripts/Simulation/SimulationTickContext.cs.meta b/Assets/GameMain/Scripts/Simulation/SimulationTickContext.cs.meta
new file mode 100644
index 0000000..6516687
--- /dev/null
+++ b/Assets/GameMain/Scripts/Simulation/SimulationTickContext.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: c4c57fcf285f488b821c9141a6d0ad09
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Assets/GameMain/Scripts/Simulation/SimulationWorld.cs b/Assets/GameMain/Scripts/Simulation/SimulationWorld.cs
new file mode 100644
index 0000000..856d916
--- /dev/null
+++ b/Assets/GameMain/Scripts/Simulation/SimulationWorld.cs
@@ -0,0 +1,119 @@
+using System.Collections.Generic;
+
+namespace Simulation
+{
+    public sealed class SimulationWorld
+    {
+        private readonly List<EnemySimData> _enemies = new List<EnemySimData>();
+        private readonly List<ProjectileSimData> _projectiles = new List<ProjectileSimData>();
+        private readonly List<PickupSimData> _pickups = new List<PickupSimData>();
+
+        public EntityBinding EnemyBinding { get; } = new EntityBinding();
+        public EntityBinding ProjectileBinding { get; } = new EntityBinding();
+        public EntityBinding PickupBinding { get; } = new EntityBinding();
+
+        public IReadOnlyList<EnemySimData> Enemies => _enemies;
+        public IReadOnlyList<ProjectileSimData> Projectiles => _projectiles;
+        public IReadOnlyList<PickupSimData> Pickups => _pickups;
+
+        public int AddEnemy(in EnemySimData simData)
+        {
+            int simulationIndex = _enemies.Count;
+            _enemies.Add(simData);
+            EnemyBinding.Bind(simData.EntityId, simulationIndex);
+            return simulationIndex;
+        }
+
+        public bool RemoveEnemyByEntityId(int entityId)
+        {
+            if (!EnemyBinding.TryGetSimulationIndex(entityId, out int simulationIndex))
+            {
+                return false;
+            }
+
+            int lastIndex = _enemies.Count - 1;
+            if (simulationIndex != lastIndex)
+            {
+                EnemySimData movedData = _enemies[lastIndex];
+                _enemies[simulationIndex] = movedData;
+                EnemyBinding.RemapIndex(movedData.EntityId, simulationIndex);
+            }
+
+            _enemies.RemoveAt(lastIndex);
+            EnemyBinding.UnbindByEntityId(entityId);
+            return true;
+        }
+
+        public int AddProjectile(in ProjectileSimData simData)
+        {
+            int simulationIndex = _projectiles.Count;
+            _projectiles.Add(simData);
+            ProjectileBinding.Bind(simData.EntityId, simulationIndex);
+            return simulationIndex;
+        }
+
+        public bool RemoveProjectileByEntityId(int entityId)
+        {
+            if (!ProjectileBinding.TryGetSimulationIndex(entityId, out int simulationIndex))
+            {
+                return false;
+            }
+
+            int lastIndex = _projectiles.Count - 1;
+            if (simulationIndex != lastIndex)
+            {
+                ProjectileSimData movedData = _projectiles[lastIndex];
+                _projectiles[simulationIndex] = movedData;
+                ProjectileBinding.RemapIndex(movedData.EntityId, simulationIndex);
+            }
+
+            _projectiles.RemoveAt(lastIndex);
+            ProjectileBinding.UnbindByEntityId(entityId);
+            return true;
+        }
+
+        public int AddPickup(in PickupSimData simData)
+        {
+            int simulationIndex = _pickups.Count;
+            _pickups.Add(simData);
+            PickupBinding.Bind(simData.EntityId, simulationIndex);
+            return simulationIndex;
+        }
+
+        public bool RemovePickupByEntityId(int entityId)
+        {
+            if (!PickupBinding.TryGetSimulationIndex(entityId, out int simulationIndex))
+            {
+                return false;
+            }
+
+            int lastIndex = _pickups.Count - 1;
+            if (simulationIndex != lastIndex)
+            {
+                PickupSimData movedData = _pickups[lastIndex];
+                _pickups[simulationIndex] = movedData;
+                PickupBinding.RemapIndex(movedData.EntityId, simulationIndex);
+            }
+
+            _pickups.RemoveAt(lastIndex);
+            PickupBinding.UnbindByEntityId(entityId);
+            return true;
+        }
+
+        public void Tick(in SimulationTickContext context)
+        {
+            _ = context;
+        }
+
+        public void Clear()
+        {
+            _enemies.Clear();
+            _projectiles.Clear();
+            _pickups.Clear();
+
+            EnemyBinding.Clear();
+            ProjectileBinding.Clear();
+            PickupBinding.Clear();
+        }
+    }
+}
diff --git a/Assets/GameMain/Scripts/Simulation/SimulationWorld.cs.meta b/Assets/GameMain/Scripts/Simulation/SimulationWorld.cs.meta
new file mode 100644
index 0000000..0b8861a
--- /dev/null
+++ b/Assets/GameMain/Scripts/Simulation/SimulationWorld.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 8a558ebbc9cb4d94946ac9f4f27914d8
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/docs/TodoList.md b/docs/TodoList.md
index 1e8b3ef..b6e8885 100644
--- a/docs/TodoList.md
+++ b/docs/TodoList.md
@@ -25,7 +25,7 @@
 - 以上问题修正后，核心流程可稳定连续跑 10 分钟无异常日志。
 
 ## 2. P1 Simulation 分层（为 Job/Burst 做结构准备）
-- [ ] Checkpoint 1：搭建 Simulation 基础骨架（仅新增，不改行为）
+- [x] Checkpoint 1：搭建 Simulation 基础骨架（仅新增，不改行为）
   - 新建目录：`Assets/GameMain/Scripts/Simulation`。
   - 新建 `SimulationWorld`，统一持有 `EnemySimData / ProjectileSimData / PickupSimData` 容器。
   - 新建 `EntityBinding`，维护 `EntityId <-> SimulationIndex` 双向映射。