Abstract: An expansion device for a virtual interface is provided. The expansion device is disposed on a mainboard of a server and is configured to acquire control of a plurality of physical resources of the server. The expansion device includes a virtual interface demand control module and a resource management module. The resource management module includes a transmission unit and a physical resource protocol unit. The virtual interface demand control module is configured to acquire control of a plurality of client facilities and arrange a demand timing of each of the client facilities to generate a plurality of interface operation signals. The transmission unit is configured to manage datastreams of the interface operation signals transmitted from the mainboard to the physical resources to decrease central processing unit (CPU) usage on the server. The physical resource protocol unit is configured to control the physical resources according to the interface operation signals.