diff --git a/logic/Preparation/Interface/IGameObj.cs b/logic/Preparation/Interface/IGameObj.cs
index 6c5205b..9be3aab 100644
--- a/logic/Preparation/Interface/IGameObj.cs
+++ b/logic/Preparation/Interface/IGameObj.cs
@@ -6,8 +6,8 @@ namespace Preparation.Interface
     {
         public GameObjType Type { get; }
         public long ID { get; }
-        public XYPosition Position { get; }  // if Square, Pos equals the center
-        public double FacingDirection { get; }
+        public XY Position { get; }  // if Square, Pos equals the center
+        public XY FacingDirection { get; }
         public bool IsRigid { get; }
         public ShapeType Shape { get; }
         public bool CanMove { get; set; }
diff --git a/logic/Preparation/Interface/IMap.cs b/logic/Preparation/Interface/IMap.cs
index 0d781b3..4ad6e18 100644
--- a/logic/Preparation/Interface/IMap.cs
+++ b/logic/Preparation/Interface/IMap.cs
@@ -13,6 +13,6 @@ namespace Preparation.Interface
         Dictionary<GameObjIdx, ReaderWriterLockSlim> GameObjLockDict { get; }
 
         public bool IsOutOfBound(IGameObj obj);
-        public IOutOfBound GetOutOfBound(XYPosition pos);  // 返回新建的一个OutOfBound对象
+        public IOutOfBound GetOutOfBound(XY pos);  // 返回新建的一个OutOfBound对象
     }
 }
diff --git a/logic/Preparation/Interface/IMoveable.cs b/logic/Preparation/Interface/IMoveable.cs
index bc16f5b..e72e14e 100644
--- a/logic/Preparation/Interface/IMoveable.cs
+++ b/logic/Preparation/Interface/IMoveable.cs
@@ -7,9 +7,9 @@ namespace Preparation.Interface
     {
         object MoveLock { get; }
         public int MoveSpeed { get; }
-        public long Move(Vector moveVec);
+        public long Move(XY moveVec);
         protected bool IgnoreCollide(IGameObj targetObj);                     // 忽略碰撞，在具体类中实现
-        public bool WillCollideWith(IGameObj? targetObj, XYPosition nextPos)  // 检查下一位置是否会和目标物碰撞
+        public bool WillCollideWith(IGameObj? targetObj, XY nextPos)  // 检查下一位置是否会和目标物碰撞
         {
             if (targetObj == null)
                 return false;
@@ -20,7 +20,7 @@ namespace Preparation.Interface
                 return false;
             if (targetObj.Shape == ShapeType.Circle)
             {
-                return XYPosition.Distance(nextPos, targetObj.Position) < targetObj.Radius + Radius;
+                return XY.Distance(nextPos, targetObj.Position) < targetObj.Radius + Radius;
             }
             else  // Square
             {
diff --git a/logic/Preparation/Utility/Vector.cs b/logic/Preparation/Utility/Vector.cs
deleted file mode 100644
index 77e2f5c..0000000
--- a/logic/Preparation/Utility/Vector.cs
+++ /dev/null
@@ -1,41 +0,0 @@
-using System;
-
-namespace Preparation.Utility
-{
-   
-    public class Vector
-    {
-        public int x;
-        public int y;
-        public Vector(int x, int y)
-        {
-            this.x = x;
-            this.y = y;
-        }
-        public override string ToString()
-        {
-            return "(" + x.ToString() + "," + y.ToString() + ")";
-        }
-        public static int operator*(Vector v1, Vector v2)
-        {
-            return (v1.x * v2.x) + (v1.y * v2.y);
-        }
-        public static Vector operator +(Vector v1, Vector v2)
-        {
-            return new Vector(v1.x + v2.x, v1.y + v2.y);
-        }
-        public static Vector operator -(Vector v1, Vector v2)
-        {
-            return new Vector(v1.x - v2.x, v1.y - v2.y);
-        }
-    }
-    public class XYPosition: Vector
-    {
-        public XYPosition(int x, int y):base(x,y){}
-       
-        public static double Distance(XYPosition p1, XYPosition p2)
-        {
-            return Math.Sqrt(((long)(p1.x - p2.x) * (p1.x - p2.x)) + ((long)(p1.y - p2.y) * (p1.y - p2.y)));
-        } 
-    }
-}
diff --git a/logic/Preparation/Utility/XY.cs b/logic/Preparation/Utility/XY.cs
new file mode 100644
index 0000000..f7536a0
--- /dev/null
+++ b/logic/Preparation/Utility/XY.cs
@@ -0,0 +1,36 @@
+using System;
+
+namespace Preparation.Utility
+{
+
+    public struct XY
+    {
+        public int x;
+        public int y;
+        public XY(int x, int y)
+        {
+            this.x = x;
+            this.y = y;
+        }
+        public override string ToString()
+        {
+            return "(" + x.ToString() + "," + y.ToString() + ")";
+        }
+        public static int operator *(XY v1, XY v2)
+        {
+            return (v1.x * v2.x) + (v1.y * v2.y);
+        }
+        public static XY operator +(XY v1, XY v2)
+        {
+            return new XY(v1.x + v2.x, v1.y + v2.y);
+        }
+        public static XY operator -(XY v1, XY v2)
+        {
+            return new XY(v1.x - v2.x, v1.y - v2.y);
+        }
+        public static double Distance(XY p1, XY p2)
+        {
+            return Math.Sqrt(((long)(p1.x - p2.x) * (p1.x - p2.x)) + ((long)(p1.y - p2.y) * (p1.y - p2.y)));
+        }
+    }
+}