diff --git a/scripts/Config.cs b/scripts/Config.cs
index 98e4d42..fa14572 100644
--- a/scripts/Config.cs
+++ b/scripts/Config.cs
@@ -20,7 +20,7 @@ public static class Config
         /// </summary>
         public const string Patrol = "Patrol";
     }
-    
+
     /// <summary>
     /// <para>Loot table ID</para>
     /// <para>战利品表ID</para>
@@ -90,7 +90,7 @@ public static class Config
     /// <para>抛出的物品击中敌人后减少的速度百分比</para>
     /// </summary>
     public const float ThrownItemsHitEnemiesReduceSpeedByPercentage = 0.5f;
-    
+
     /// <summary>
     /// <para>How much blood does a heart represent</para>
     /// <para>一颗心代表多少血量</para>
diff --git a/scripts/behaviorTree/BehaviorNode.cs b/scripts/behaviorTree/BehaviorNode.cs
index f2f8c58..202e05b 100644
--- a/scripts/behaviorTree/BehaviorNode.cs
+++ b/scripts/behaviorTree/BehaviorNode.cs
@@ -25,6 +25,7 @@ public partial class BehaviorNode : Node2D
         {
             return;
         }
+
         Root.Execute(isPhysicsProcess, delta);
     }
 }
\ No newline at end of file
diff --git a/scripts/behaviorTree/ai/AiPickNode.cs b/scripts/behaviorTree/ai/AiPickNode.cs
index 9f98d0e..3f09278 100644
--- a/scripts/behaviorTree/ai/AiPickNode.cs
+++ b/scripts/behaviorTree/ai/AiPickNode.cs
@@ -1,5 +1,4 @@
 using ColdMint.scripts.character;
-
 using WeaponTemplate = ColdMint.scripts.weapon.WeaponTemplate;
 
 namespace ColdMint.scripts.behaviorTree.ai;
@@ -10,8 +9,6 @@ namespace ColdMint.scripts.behaviorTree.ai;
 /// </summary>
 public class AiPickNode : BehaviorTreeNodeTemplate
 {
-
-
     public AiCharacter? Character { get; set; }
 
     public override int Execute(bool isPhysicsProcess, double delta)
@@ -51,7 +48,7 @@ public class AiPickNode : BehaviorTreeNodeTemplate
             {
                 closestDistance = distanceLength;
                 closestWeapon = weaponTemplate;
-            }   
+            }
         }
 
         //绘制一条线，从AI到武器
diff --git a/scripts/character/Player.cs b/scripts/character/Player.cs
index b3b0026..7616379 100644
--- a/scripts/character/Player.cs
+++ b/scripts/character/Player.cs
@@ -3,6 +3,7 @@ using System.Text;
 using System.Threading.Tasks;
 using ColdMint.scripts.damage;
 using ColdMint.scripts.deathInfo;
+using ColdMint.scripts.debug;
 using ColdMint.scripts.inventory;
 using ColdMint.scripts.map.events;
 using ColdMint.scripts.utils;
@@ -49,6 +50,7 @@ public partial class Player : CharacterTemplate
     {
         base._Ready();
         CharacterName = TranslationServerUtils.Translate("default_player_name");
+        LogCat.LogWithFormat("player_spawn_debug", ReadOnlyCharacterName, GlobalPosition);
         _floatLabelPackedScene = GD.Load<PackedScene>("res://prefab/ui/FloatLabel.tscn");
         _parabola = GetNode<Line2D>("Parabola");
         _platformDetectionRayCast2D = GetNode<RayCast2D>("PlatformDetectionRayCast");
diff --git a/scripts/inventory/HotBar.cs b/scripts/inventory/HotBar.cs
index 16ae362..70ef617 100644
--- a/scripts/inventory/HotBar.cs
+++ b/scripts/inventory/HotBar.cs
@@ -1,5 +1,3 @@
-using System;
-using ColdMint.scripts.map.events;
 using ColdMint.scripts.utils;
 using Godot;
 
@@ -13,18 +11,20 @@ public partial class HotBar : HBoxContainer
 {
     private IItemContainer? _itemContainer;
 
-    Action<SelectedItemSlotChangeEvent>? SelectedItemSlotChangeEvent { get; set; }
 
     public override void _Ready()
     {
         base._Ready();
         _itemContainer = new UniversalItemContainer();
         _itemContainer.SupportSelect = true;
-        _itemContainer.SelectedItemSlotChangeEvent += SelectedItemSlotChangeEvent;
         NodeUtils.DeleteAllChild(this);
         for (var i = 0; i < Config.HotBarSize; i++)
         {
-            _itemContainer.AddItemSlot(this);
+            var itemSlotNode = _itemContainer.AddItemSlot(this);
+            if (itemSlotNode != null)
+            {
+                itemSlotNode.BackpackAllowed = true;
+            }
         }
     }
 
@@ -113,13 +113,4 @@ public partial class HotBar : HBoxContainer
     {
         return _itemContainer;
     }
-
-    public override void _ExitTree()
-    {
-        base._ExitTree();
-        if (_itemContainer != null)
-        {
-            _itemContainer.SelectedItemSlotChangeEvent -= SelectedItemSlotChangeEvent;
-        }
-    }
 }
\ No newline at end of file
diff --git a/scripts/inventory/ItemSlotNode.cs b/scripts/inventory/ItemSlotNode.cs
index 7f50852..7a120f1 100644
--- a/scripts/inventory/ItemSlotNode.cs
+++ b/scripts/inventory/ItemSlotNode.cs
@@ -85,7 +85,7 @@ public partial class ItemSlotNode : MarginContainer
             return false;
         }
 
-        return _item == null;
+        return CanAddItem(item);
     }
 
     /// <summary>
@@ -125,7 +125,7 @@ public partial class ItemSlotNode : MarginContainer
         {
             return null;
         }
-        
+
         if (number > _item.Quantity)
         {
             //The number of item instances created exceeds the current number of items
@@ -163,9 +163,15 @@ public partial class ItemSlotNode : MarginContainer
         }
 
         itemSlotNode.Item = null;
-        Item = item;
+        AddItem(item);
     }
 
+    /// <summary>
+    /// <para>Whether to place a backpack in the current slot</para>
+    /// <para>当前槽位是否允许放置背包</para>
+    /// </summary>
+    public bool BackpackAllowed { get; set; }
+
     public bool IsSelect
     {
         get => _isSelect;
@@ -282,6 +288,12 @@ public partial class ItemSlotNode : MarginContainer
 
     public bool CanAddItem(IItem item)
     {
+        if (!BackpackAllowed && item is Packsack)
+        {
+            //如果禁止放置背包，且新物品是背包
+            return false;
+        }
+
         if (_item == null)
         {
             //If there is no item in the current item slot, it is allowed to add.
@@ -352,6 +364,7 @@ public partial class ItemSlotNode : MarginContainer
         {
             node2D.QueueFree();
         }
+
         UpdateQuantityLabel();
         return true;
     }
diff --git a/scripts/inventory/Packsack.cs b/scripts/inventory/Packsack.cs
index 0fe1e20..031127f 100644
--- a/scripts/inventory/Packsack.cs
+++ b/scripts/inventory/Packsack.cs
@@ -30,7 +30,7 @@ public partial class Packsack : PickAbleTemplate
             _packsackUi = NodeUtils.InstantiatePackedScene<PacksackUi>(_packedScene);
             if (_packsackUi != null)
             {
-                NodeUtils.CallDeferredReparent(this, _packsackUi);
+                NodeUtils.CallDeferredAddChild(NodeUtils.FindContainerNode(_packsackUi, this), _packsackUi);
                 _packsackUi.Title = Name;
                 _packsackUi.ItemContainer = ItemContainer;
             }
diff --git a/scripts/map/AiCharacterSpawn.cs b/scripts/map/AiCharacterSpawn.cs
index c8d953e..03d598a 100644
--- a/scripts/map/AiCharacterSpawn.cs
+++ b/scripts/map/AiCharacterSpawn.cs
@@ -48,8 +48,8 @@ public partial class AiCharacterSpawn : Marker2D
             return;
         }
 
-        NodeUtils.CallDeferredAddChild(NodeUtils.FindContainerNode(aiCharacter, this), aiCharacter);
-        aiCharacter.Position = GlobalPosition;
+        NodeUtils.CallDeferredAddChild(GameSceneNodeHolder.AiCharacterContainer, aiCharacter);
+        aiCharacter.GlobalPosition = GlobalPosition;
     }
 
     public override void _ExitTree()
diff --git a/scripts/map/PlayerSpawn.cs b/scripts/map/PlayerSpawn.cs
index 8206fe6..a1c3df4 100644
--- a/scripts/map/PlayerSpawn.cs
+++ b/scripts/map/PlayerSpawn.cs
@@ -28,7 +28,7 @@ public partial class PlayerSpawn : Marker2D
         if (GameSceneNodeHolder.Player != null)
         {
             GameSceneNodeHolder.Player.ProcessMode = ProcessModeEnum.Inherit;
-            GameSceneNodeHolder.Player.Position = GlobalPosition;
+            GameSceneNodeHolder.Player.GlobalPosition = GlobalPosition;
             GameSceneNodeHolder.Player.Revive(GameSceneNodeHolder.Player.MaxHp);
             return;
         }
@@ -60,7 +60,9 @@ public partial class PlayerSpawn : Marker2D
             return;
         }
 
-        NodeUtils.CallDeferredAddChild(NodeUtils.FindContainerNode(playerNode, this), playerNode);
+        //The player's parent node must be GameSceneNodeHolder PlayerContainer.
+        //玩家的父节点必须是GameSceneNodeHolder.PlayerContainer。
+        NodeUtils.CallDeferredAddChild(GameSceneNodeHolder.PlayerContainer, playerNode);
         var itemContainer = GameSceneNodeHolder.HotBar?.GetItemContainer();
         if (itemContainer == null)
         {
@@ -71,8 +73,7 @@ public partial class PlayerSpawn : Marker2D
 
         playerNode.ItemContainer = itemContainer;
         GameSceneNodeHolder.Player = playerNode;
-        playerNode.Position = GlobalPosition;
-        LogCat.LogWithFormat("player_spawn_debug", playerNode.ReadOnlyCharacterName, playerNode.Position);
+        playerNode.GlobalPosition = GlobalPosition;
     }
 
     private void MapGenerationCompleteEvent(MapGenerationCompleteEvent mapGenerationCompleteEvent)
diff --git a/scripts/map/events/GameReplayEvent.cs b/scripts/map/events/GameReplayEvent.cs
index f9e7de1..835abf1 100644
--- a/scripts/map/events/GameReplayEvent.cs
+++ b/scripts/map/events/GameReplayEvent.cs
@@ -4,7 +4,4 @@
 /// <para>Game replay event</para>
 /// <para>游戏重玩事件</para>
 /// </summary>
-public class GameReplayEvent
-{
-    
-}
\ No newline at end of file
+public class GameReplayEvent;
\ No newline at end of file
diff --git a/scripts/map/events/MapGenerationStartEvent.cs b/scripts/map/events/MapGenerationStartEvent.cs
index e18d7a8..6c1fd5a 100644
--- a/scripts/map/events/MapGenerationStartEvent.cs
+++ b/scripts/map/events/MapGenerationStartEvent.cs
@@ -4,7 +4,4 @@
 /// <para>The map generator starts the event</para>
 /// <para>地图生成器启动事件</para>
 /// </summary>
-public class MapGenerationStartEvent
-{
-    
-}
\ No newline at end of file
+public class MapGenerationStartEvent;
\ No newline at end of file
diff --git a/scripts/projectile/Projectile.cs b/scripts/projectile/Projectile.cs
index be694ce..ec36955 100644
--- a/scripts/projectile/Projectile.cs
+++ b/scripts/projectile/Projectile.cs
@@ -1,6 +1,3 @@
 namespace ColdMint.scripts.projectile;
 
-public partial class Projectile : ProjectileTemplate
-{
-	
-}
+public partial class Projectile : ProjectileTemplate;