diff --git a/Cad/BlockRawFreeForgeNoRoundHeadDrawer.cs b/Cad/BlockRawFreeForgeNoRoundHeadDrawer.cs
index 6d31b70..7082461 100644
--- a/Cad/BlockRawFreeForgeNoRoundHeadDrawer.cs
+++ b/Cad/BlockRawFreeForgeNoRoundHeadDrawer.cs
@@ -276,10 +276,12 @@ namespace CadParamPluging.Cad
                         dimText += $"\\X({FormatDimNumber(valPrime.Value, null)})";
                     }
 
+                    // 修正：引线向下延伸 innerFilletR，以接触直边
+                    double dimYStart = oy + H - innerFilletR;
                     AddLinearDim(
                         ctx,
-                        new Point3d(xSectionLeft, oy + H, 0),
-                        new Point3d(xSectionRight, oy + H, 0),
+                        new Point3d(xSectionLeft, dimYStart, 0),
+                        new Point3d(xSectionRight, dimYStart, 0),
                         new Point3d((xSectionLeft + xSectionRight) / 2, oy + H + 15, 0),
                         0,
                         dimText);
diff --git a/Cad/BlockRawFreeForgeRoundHeadDrawer.cs b/Cad/BlockRawFreeForgeRoundHeadDrawer.cs
index ab81329..24b0401 100644
--- a/Cad/BlockRawFreeForgeRoundHeadDrawer.cs
+++ b/Cad/BlockRawFreeForgeRoundHeadDrawer.cs
@@ -272,10 +272,13 @@ namespace CadParamPluging.Cad
                         dimText += $"\\X({FeatureDrivenDrawer.FormatDimNumber(valPrime.Value, null)})";
                     }
 
+                    // 修正：引线向下延伸 sectionFilletR，以接触直边
+                    // sectionFilletR 是剖面处的圆角半径
+                    double dimYStart = oy + H - sectionFilletR;
                     AddLinearDim(
                         ctx,
-                        new Point3d(xSectionLeft, oy + H, 0),
-                        new Point3d(xSectionRight, oy + H, 0),
+                        new Point3d(xSectionLeft, dimYStart, 0),
+                        new Point3d(xSectionRight, dimYStart, 0),
                         new Point3d((xSectionLeft + xSectionRight) / 2, oy + H + 15, 0),
                         0,
                         dimText);