diff --git a/__test__/Polyline/rectOffset.test.ts b/__test__/Polyline/rectOffset.test.ts
index 377e68a54..130095ded 100644
--- a/__test__/Polyline/rectOffset.test.ts
+++ b/__test__/Polyline/rectOffset.test.ts
@@ -92,4 +92,14 @@ describe("矩形偏移", () =>
         expect(rectInfo).toMatchSnapshot();
         expect(pl.LineData).toMatchSnapshot();
     });
+
+    test('不是矩形', () =>
+    {
+        let d =
+            [1, "Polyline", 10, 2, 0, 0, 0, 7, 0, [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1], 0, 0, 1, [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1], 0, 0, 1, 2, 4, [49.95586871614796, 0], 0, [49.96160816995791, 0], 0, [49.95586871614796, 2352.839413948619], 0, [49.95586871614796, 2352.0000499849994], 0, true];
+
+        let pl = LoadEntityFromFileData(d)[0] as Polyline;
+        let rectInfo = IsRect(pl);
+        expect(rectInfo).toBeUndefined();
+    });
 });
diff --git a/src/Common/CurveUtils.ts b/src/Common/CurveUtils.ts
index 758956eb6..dab5c3267 100644
--- a/src/Common/CurveUtils.ts
+++ b/src/Common/CurveUtils.ts
@@ -9,7 +9,7 @@ import { IsPointInBowArc } from '../DatabaseServices/PointInPolyline';
 import { Spline } from '../DatabaseServices/Spline';
 import { Count } from '../Geometry/Count';
 import { CurveMap, Vertice } from '../Geometry/CurveMap';
-import { AsVector2, AsVector3, equaln, equalv2, equalv3, isIntersect, isParallelTo, XAxis, YAxis, ZAxis, ZeroVec } from '../Geometry/GeUtils';
+import { AsVector2, AsVector3, XAxis, YAxis, ZAxis, ZeroVec, equaln, equalv2, equalv3, isIntersect, isParallelTo } from '../Geometry/GeUtils';
 import { Vec3 } from '../Geometry/IVec3';
 import { Matrix2 } from '../Geometry/Matrix2';
 import { Orbit } from '../Geometry/Orbit';
@@ -585,7 +585,7 @@ export function IsRect(cu: Curve): IRectInfo | undefined
             preV.copy(nowV).negate();//翻转它 以便下一次计算
         }
 
-        if (pts4.length === 4 && !crossV)//没有90度 (就不是矩形)
+        if (pts4.length !== 4 || !crossV)//没有90度 (就不是矩形)
             return;
 
         let rectOCS: Matrix4;