diff --git a/src/IFoxCAD.Cad/ExtensionMethod/CurveEx.cs b/src/IFoxCAD.Cad/ExtensionMethod/CurveEx.cs
index ba8f5d1850473fff80811854da3de62755267ec4..fd3bf8362e3840362e3c1ebaf25f0b42d3623322 100644
--- a/src/IFoxCAD.Cad/ExtensionMethod/CurveEx.cs
+++ b/src/IFoxCAD.Cad/ExtensionMethod/CurveEx.cs
@@ -644,7 +644,7 @@ public static EllipticalArc3d ToEllipticalArc3d(this Arc arc)
         public static NurbCurve3d ToNurbCurve3d(this Arc arc)
         {
             return new NurbCurve3d(ToEllipticalArc3d(arc));
-        }
+        } 
 
         #endregion Arc
 
diff --git a/src/IFoxCAD.Cad/ExtensionMethod/EntityEx.cs b/src/IFoxCAD.Cad/ExtensionMethod/EntityEx.cs
index 38efca400d715572ef61b7dc806b06a82d54a2ad..90e0dbb31369dcd899003a97599b01dd677f1620 100644
--- a/src/IFoxCAD.Cad/ExtensionMethod/EntityEx.cs
+++ b/src/IFoxCAD.Cad/ExtensionMethod/EntityEx.cs
@@ -232,5 +232,112 @@ public static string GetUnFormatString(this MText mt)
             return string.Join("", strs.ToArray());
         }
         #endregion
+
+        #region 圆弧
+
+        /// <summary>
+        /// 根据圆心、起点和终点来创建圆弧(二维)
+        /// </summary>
+        /// <param name="arc">圆弧对象</param>
+        /// <param name="startPoint">起点</param>
+        /// <param name="centerPoint">圆心</param>
+        /// <param name="endPoint">终点</param>
+        /// <returns>圆弧</returns>
+        public static Arc CreateArcSCE(Point3d startPoint, Point3d centerPoint, Point3d endPoint)
+        {
+            Arc arc = new();
+            arc.Center = centerPoint;
+            arc.Radius = centerPoint.DistanceTo(startPoint);
+            Vector2d startVector = new(startPoint.X - centerPoint.X, startPoint.Y - centerPoint.Y);
+            Vector2d endVector = new(endPoint.X - centerPoint.X, endPoint.Y - centerPoint.Y);
+            //计算起始和终止角度
+            arc.StartAngle = startVector.Angle;
+            arc.EndAngle = endVector.Angle;
+            return arc;
+        }
+        /// <summary>
+        /// 三点法创建圆弧(二维)
+        /// </summary>
+        /// <param name="arc">圆弧对象</param>
+        /// <param name="startPoint">起点</param>
+        /// <param name="pointOnArc">圆弧上的点</param>
+        /// <param name="endPoint">终点</param>
+        /// <returns>圆弧</returns>
+        public static Arc CreateArc(Point3d startPoint, Point3d pointOnArc, Point3d endPoint)
+        {
+            //创建一个几何类的圆弧对象
+            CircularArc3d geArc = new(startPoint, pointOnArc, endPoint);
+            //将几何类圆弧对象的圆心和半径赋值给圆弧
+#if ac2009
+            return geArc.ToArc();
+#elif ac2013
+            return (Arc)Curve.CreateFromGeCurve(geArc);
+#endif
+        }
+
+        /// <summary>
+        /// 根据起点、圆心和圆弧角度创建圆弧(二维)
+        /// </summary>
+        /// <param name="arc">圆弧对象</param>
+        /// <param name="startPoint">起点</param>
+        /// <param name="centerPoint">圆心</param>
+        /// <param name="angle">圆弧角度</param>
+        /// <returns>圆弧</returns>
+        public static Arc CreateArc(Point3d startPoint, Point3d centerPoint, double angle)
+        {
+            Arc arc = new();
+            arc.Center = centerPoint;
+            arc.Radius = centerPoint.DistanceTo(startPoint);
+            Vector2d startVector = new(startPoint.X - centerPoint.X, startPoint.Y - centerPoint.Y);
+            arc.StartAngle = startVector.Angle;
+            arc.EndAngle = startVector.Angle + angle;
+            return arc;
+        }
+
+        #endregion
+
+        #region 圆
+
+        /// <summary>
+        /// 两点创建圆(两点中点为圆心)
+        /// </summary>
+        /// <param name="startPoint">起点</param>
+        /// <param name="endPoint">终点</param>
+        /// <returns>圆</returns>
+        public static Circle CreateCircle(Point3d startPoint, Point3d endPoint)
+        {
+            Circle circle = new();
+            circle.Center = startPoint.GetMidPointTo(endPoint);
+            circle.Radius = startPoint.DistanceTo(endPoint) * 0.5;
+            return circle;
+        }
+
+        /// <summary>
+        /// 三点法创建圆(失败则返回Null)
+        /// </summary>
+        /// <param name="pt1">第一点</param>
+        /// <param name="pt2">第二点</param>
+        /// <param name="pt3">第三点</param>
+        /// <returns>圆</returns>
+        public static Circle CreateCircle(Point3d pt1, Point3d pt2, Point3d pt3)
+        {
+            //先判断三点是否共线,得到pt1点指向pt2、pt2点的矢量
+            Vector3d va = pt1.GetVectorTo(pt2);
+            Vector3d vb = pt1.GetVectorTo(pt3);
+            //如两矢量夹角为0或180度（π弧度),则三点共线.
+            if (va.GetAngleTo(vb) == 0 | va.GetAngleTo(vb) == Math.PI)
+            {
+                return null;
+            }
+            else
+            {
+                //创建一个几何类的圆弧对象
+                CircularArc3d geArc = new(pt1, pt2, pt3);
+                geArc.ToCircle();
+                return geArc.ToCircle();
+            }
+        }
+
+        #endregion
     }
 }
diff --git a/src/IFoxCAD.Cad/ExtensionMethod/GeometryEx.cs b/src/IFoxCAD.Cad/ExtensionMethod/GeometryEx.cs
index 46eee82feffaf3aba53c1e1071ed8c435214420d..1f15466440674f7099246d3b1c6cfa74f4f04ccd 100644
--- a/src/IFoxCAD.Cad/ExtensionMethod/GeometryEx.cs
+++ b/src/IFoxCAD.Cad/ExtensionMethod/GeometryEx.cs
@@ -58,7 +58,7 @@ public enum PointOnRegionType
     /// </summary>
     public static class GeometryEx
     {
-        
+
         #region Point&Circle
 
         /// <summary>
@@ -719,6 +719,27 @@ public static Point2d Point2d(this Point3d pt)
             return new Point2d(pt.X, pt.Y);
         }
 
+        /// <summary>
+        /// 将二维点转换为三维点
+        /// </summary>
+        /// <param name="pt">二维点</param>
+        /// <returns>三维点</returns>
+        public static Point3d Point3d(this Point2d pt)
+        {
+            return new Point3d(pt.X, pt.Y, 0);
+        }
+
+        /// <summary>
+        /// 获取两个点之间的中点
+        /// </summary>
+        /// <param name="pt1">第一点</param>
+        /// <param name="pt2">第二点</param>
+        /// <returns>返回两个点之间的中点</returns>
+        public static Point3d GetMidPointTo(this Point3d pt1, Point3d pt2)
+        {
+            return new Point3d((pt1.X + pt2.X) * 0.5, (pt1.Y + pt2.Y) * 0.5, (pt1.Z + pt2.Z) * 0.5);
+        }
+
         public static IEnumerable<Point2d> Point2d(this IEnumerable<Point3d> pts)
         {
             return pts.Select(pt => pt.Point2d());
diff --git a/src/IFoxCAD.Cad/ExtensionMethod/SymbolTableRecordEx.cs b/src/IFoxCAD.Cad/ExtensionMethod/SymbolTableRecordEx.cs
index b3b98907174e38f06a83e4f0740ae173cd05d29f..2c874114b86d7a6b8084d4c3f99ae775878ee534 100644
--- a/src/IFoxCAD.Cad/ExtensionMethod/SymbolTableRecordEx.cs
+++ b/src/IFoxCAD.Cad/ExtensionMethod/SymbolTableRecordEx.cs
@@ -125,25 +125,11 @@ public static ObjectId AddCircle(this BlockTableRecord btr, Point3d center, doub
         /// <param name="action">圆属性设置委托</param>
         /// <param name="trans">事务管理器</param>
         /// <returns>三点有外接圆则返回圆的id，否则返回ObjectId.Null</returns>
-        public static ObjectId AddCircle(this BlockTableRecord btr, Point3d p0, Point3d p1, Point3d p2, Action<Circle> action = default, Transaction trans = default)
+        public static ObjectId AddCircle(this BlockTableRecord btr, Point3d p0, Point3d p1, Point3d p2,
+            Action<Circle> action = default, Transaction trans = default)
         {
-            var dx1 = p1.X - p0.X;
-            var dy1 = p1.Y - p0.Y;
-            var dx2 = p2.X - p0.X;
-            var dy2 = p2.Y - p0.Y;
-
-            var d = dx1 * dy2 - dx2 * dy1;
-
-            if (d != 0.0)
-            {
-                var d2 = d * 2;
-                var c1 = (p0.X + p1.X) * dx1 + (p0.Y + p1.Y) * dy1;
-                var c2 = (p0.X + p2.X) * dx2 + (p0.Y + p2.Y) * dy2;
-                var ce = new Point3d((c1 * dy2 - c2 * dy1) / d2, (c2 * dx1 - c1 * dx2) / d2, 0);
-                var circle = new Circle(ce, Vector3d.ZAxis, p0.DistanceTo(ce));
-                return btr.AddEnt(circle, action, trans);
-            }
-            return ObjectId.Null;
+            Circle circle = EntityEx.CreateCircle(p0, p1, p2);
+            return circle is not null ? btr.AddEnt(circle, action, trans) : throw new ArgumentNullException(nameof(circle), "对象为 null");
         }
         /// <summary>
         /// 在指定的绘图空间添加轻多段线
@@ -181,13 +167,8 @@ public static ObjectId AddPline(this BlockTableRecord btr, List<Point3d> pts, Li
         /// <returns>圆弧id</returns>
         public static ObjectId AddArc(this BlockTableRecord btr, Point3d startPoint, Point3d pointOnArc, Point3d endPoint, Action<Arc> action = default, Transaction trans = default)
         {
-
-            var arc = new CircularArc3d(startPoint, pointOnArc, endPoint);
-#if ac2009
-            return btr.AddEnt(arc.ToArc(), action, trans);
-#elif ac2013
-            return btr.AddEnt(Curve.CreateFromGeCurve(arc) as Arc, action, trans);
-#endif           
+            var arc = EntityEx.CreateArc(startPoint, pointOnArc, endPoint);
+            return btr.AddEnt(arc, action, trans);
         }
         #endregion
 
diff --git a/tests/DBTrans.test/Test.cs b/tests/DBTrans.test/Test.cs
index ae6e9b8a3239383ab36ac87c7fdd488d111c55be..14e956b4bb4061201c6ce31b9931926fe6d2955c 100644
--- a/tests/DBTrans.test/Test.cs
+++ b/tests/DBTrans.test/Test.cs
@@ -69,7 +69,32 @@ public void Addent()
         public void drawarc()
         {
             using var tr = new DBTrans();
-            tr.CurrentSpace.AddArc(new Point3d(0, 0, 0), new Point3d(1, 1, 0), new Point3d(2, 0, 0));
+            Arc arc1 = EntityEx.CreateArcSCE(new Point3d(2, 0, 0), new Point3d(0, 0, 0), new Point3d(0, 2, 0));//起点，圆心，终点
+            Arc arc2 = EntityEx.CreateArc(new Point3d(4, 0, 0), new Point3d(0, 0, 0), Math.PI / 2);//起点，圆心，弧度
+            Arc arc3 = EntityEx.CreateArc(new Point3d(1, 0, 0), new Point3d(0, 0, 0), new Point3d(0, 1, 0));//起点，圆上一点，终点
+            tr.CurrentSpace.AddEntity(arc1, arc2, arc3);
+            tr.CurrentSpace.AddArc(new Point3d(0, 0, 0), new Point3d(1, 1, 0), new Point3d(2, 0, 0));//起点，圆上一点，终点
+        }
+
+        [CommandMethod("drawcircle")]
+        public void draCircle()
+        {
+            using var tr = new DBTrans();
+            Circle circle1 = EntityEx.CreateCircle(new Point3d(0, 0, 0), new Point3d(1, 0, 0));//起点，终点
+            Circle circle2 = EntityEx.CreateCircle(new Point3d(-2, 0, 0), new Point3d(2, 0, 0), new Point3d(0, 2, 0));//三点画圆，成功
+            Circle circle3 = EntityEx.CreateCircle(new Point3d(-2, 0, 0), new Point3d(0, 0, 0), new Point3d(2, 0, 0));//起点，圆心，终点，失败
+            tr.CurrentSpace.AddEntity(circle1, circle2);
+            if (circle3 is not null)
+            {
+                tr.CurrentSpace.AddEntity(circle3);
+            }
+            else
+            {
+                tr.Editor.WriteMessage("三点画圆失败");
+            }
+            tr.CurrentSpace.AddEntity(circle3);
+            tr.CurrentSpace.AddCircle(new Point3d(0, 0, 0), new Point3d(1, 1, 0), new Point3d(2, 0, 0));//三点画圆，成功
+            tr.CurrentSpace.AddCircle(new Point3d(0, 0, 0), new Point3d(1, 1, 0), new Point3d(2, 2, 0));//起点，圆上一点，终点(共线)
         }
 
         [CommandMethod("layertest")]