diff --git a/src/Geometry/SpaceParse/SpaceParse.ts b/src/Geometry/SpaceParse/SpaceParse.ts
index 8e05c0476..be53567b4 100644
--- a/src/Geometry/SpaceParse/SpaceParse.ts
+++ b/src/Geometry/SpaceParse/SpaceParse.ts
@@ -67,7 +67,7 @@ export class SpaceParse
     }
     async parseSingleBoard(br: Board)
     {
-        let dtRes = await app.m_Editor.GetDistance({ Msg: "只有一块板,请输入延伸距离:" });
+        let dtRes = await app.m_Editor.GetDistance({ Msg: "只有一块板,请输入延伸距离:", Default: 300 });
         if (dtRes.Status !== PromptStatus.Cancel)
         {
             let dist = dtRes.Value / 100;