diff --git a/iOS/BDAlphaPlayer/Classes/Render/BDAlphaPlayerMetalRenderer.m b/iOS/BDAlphaPlayer/Classes/Render/BDAlphaPlayerMetalRenderer.m
index 1d23e4c..b4e06ee 100644
--- a/iOS/BDAlphaPlayer/Classes/Render/BDAlphaPlayerMetalRenderer.m
+++ b/iOS/BDAlphaPlayer/Classes/Render/BDAlphaPlayerMetalRenderer.m
@@ -132,7 +132,7 @@ -(void)setupPipeline
     pipelineStateDescriptor.colorAttachments[0].pixelFormat = self.mtkView.colorPixelFormat;
     pipelineStateDescriptor.colorAttachments[0].blendingEnabled = true;
     pipelineStateDescriptor.colorAttachments[0].rgbBlendOperation = MTLBlendOperationAdd;
-    pipelineStateDescriptor.colorAttachments[0].sourceRGBBlendFactor = MTLBlendFactorOne;
+    pipelineStateDescriptor.colorAttachments[0].sourceRGBBlendFactor = MTLBlendFactorSourceAlpha;
     pipelineStateDescriptor.colorAttachments[0].destinationRGBBlendFactor = MTLBlendFactorOne;
     pipelineStateDescriptor.colorAttachments[0].alphaBlendOperation = MTLBlendOperationMin;
     pipelineStateDescriptor.colorAttachments[0].sourceAlphaBlendFactor = MTLBlendFactorOne;