diff --git a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
index 78811419bf..b2d76d67af 100644
--- a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
+++ b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
@@ -199,6 +199,7 @@ CreateRootBridge (
       break;
     default:
       ASSERT (FALSE);
+      Aperture = NULL;
       break;
     }
     RootBridge->ResAllocNode[Index].Type     = Index;