diff --git a/simple-mind-map/src/layouts/Timeline.js b/simple-mind-map/src/layouts/Timeline.js
index d45add64..85912d7e 100644
--- a/simple-mind-map/src/layouts/Timeline.js
+++ b/simple-mind-map/src/layouts/Timeline.js
@@ -143,7 +143,7 @@ class Timeline extends Base {
                   : 0)
               )
             }, 0) +
-            (len + 1) * marginY
+            len * marginY
           this.updateBrothersTop(node, totalHeight)
         }
       },