diff --git a/CHANGELOG-PRERELEASE.md b/CHANGELOG-PRERELEASE.md
index 26add3158..8b67d0d11 100644
--- a/CHANGELOG-PRERELEASE.md
+++ b/CHANGELOG-PRERELEASE.md
@@ -20,6 +20,7 @@ The format is based on [Keep a Changelog].
 
 ### Fixed
 - UnusedBonesByReferenceTool error with SMR without mesh `#280`
+- MergeSkinnedMesh doesn't work well with eyelids `#284`
 
 ### Security
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index bb360684e..aa4d92942 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,7 @@ The format is based on [Keep a Changelog].
 
 ### Fixed
 - UnusedBonesByReferenceTool error with SMR without mesh `#280`
+- MergeSkinnedMesh doesn't work well with eyelids `#284`
 
 ### Security
 
diff --git a/Editor/Processors/SkinnedMeshes/MergeSkinnedMeshProcessor.cs b/Editor/Processors/SkinnedMeshes/MergeSkinnedMeshProcessor.cs
index ebe91075a..09c465735 100644
--- a/Editor/Processors/SkinnedMeshes/MergeSkinnedMeshProcessor.cs
+++ b/Editor/Processors/SkinnedMeshes/MergeSkinnedMeshProcessor.cs
@@ -69,7 +69,7 @@ TexCoordStatus TexCoordStatusMax(TexCoordStatus x, TexCoordStatus y) =>
                     var newIndex = target.BlendShapes.FindIndex(x => x.name == name);
                     if (newIndex == -1)
                     {
-                        newIndex = target.BlendShapes.Count - 1;
+                        newIndex = target.BlendShapes.Count;
                         target.BlendShapes.Add((name, weight));
                     }