diff --git a/src/GraphicsSystem/Viewer.ts b/src/GraphicsSystem/Viewer.ts
index 4a3af255e..0d6a2442d 100644
--- a/src/GraphicsSystem/Viewer.ts
+++ b/src/GraphicsSystem/Viewer.ts
@@ -591,6 +591,7 @@ export class Viewer
             let i = 0;
             down.progress = 0.1;
             let brs: Board[] = [];
+            let pre = Date.now();
             for (let index = 0; index < db.ModelSpace.Entitys.length; index++)
             {
                 let en = db.ModelSpace.Entitys[index];
@@ -598,12 +599,14 @@ export class Viewer
                     brs.push(en);
                 this._Scene.add(en.DrawObject);
                 i++;
-                if (i === 50)
+                let now = Date.now();
+                if (i === 50 || now - pre > 100)
                 {
                     down.progress = 0.1 + index / db.ModelSpace.Entitys.length;
                     await Sleep(1);
                     i = 0;
                 }
+                pre = now;
             }
 
             down.progress = 1;
@@ -623,11 +626,13 @@ export class Viewer
             {
                 if (!br.IsErase && br.Visible)
                     br.GetDrawObjectFromRenderType(RenderType.Physical);
-                if (i === 30)
+                let now = Date.now();
+                if (now - pre > 100 || i === 30)
                 {
                     await Sleep(1);
                     i = 0;
                 }
+                pre = now;
             }
 
             down.progressName = "";