diff --git a/src/DatabaseServices/Entity/Arc.ts b/src/DatabaseServices/Entity/Arc.ts
index 1d8481289..ef3cdd3b5 100644
--- a/src/DatabaseServices/Entity/Arc.ts
+++ b/src/DatabaseServices/Entity/Arc.ts
@@ -272,15 +272,13 @@ export class Arc extends Curve
         let surplusAngleHalf = Math.PI - allAn / 2;
 
         if (ptAllAn > allAn + surplusAngleHalf)//返回负数
-        {
             return ((ptAllAn - allAn) - (surplusAngleHalf * 2)) / allAn;
-        }
         else//返回正数
             return ptAllAn / allAn;
     }
 
     /**
-     * Gets param at angle2
+     * 根据角度获得参数,不过在这里我们可以指定我们是要获取前面的参数还是后面的参数(正负)
      * @param an
      * @param [isStart] true:返回负数，false 返回正数
      * @returns
@@ -295,9 +293,7 @@ export class Arc extends Curve
         let surplusAngleHalf = Math.PI - allAn / 2;
 
         if (isStart)//返回负数
-        {
             return ((ptAllAn - allAn) - (surplusAngleHalf * 2)) / allAn;
-        }
         else//返回正数
             return ptAllAn / allAn;
     }
@@ -505,7 +501,7 @@ export class Arc extends Curve
         if (this._Clockwise)
         {
             if (this._StartAngle > endAngle)
-                return this.StartAngle - endAngle;
+                return this._StartAngle - endAngle;
             else //越过0点绘制圆弧
                 return (Math.PI * 2) - (endAngle - this._StartAngle);
         }