diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.c
index c48e3bba96..a1654c0025 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.c
@@ -244,6 +244,11 @@ PciBusDriverBindingStart (
   EFI_DEVICE_PATH_PROTOCOL        *ParentDevicePath;
   EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL *PciRootBridgeIo;
 
+  //
+  // Initialize PciRootBridgeIo to suppress incorrect compiler warning.
+  //
+  PciRootBridgeIo = NULL;
+
   //
   // Check RemainingDevicePath validation
   //