A video interworking gateway device, a system and method for implementing a video phone call service are provided, which processes the service when a call object changes if the call is not disconnected. The system includes a video interworking gateway device, a broadband resource device and a bearer connection device. The video interworking gateway device negotiates with a calling H.324 entity about parameters, and connects the calling H.324 entity to the broadband resource device on obtaining negotiation parameters of the calling H.324 entity; the video interworking gateway device negotiates with a called H.324 entity about parameters, obtains negotiation parameters of the called H.324 entity, exchanges the negotiation parameters of the calling H.324 entity and those of the called H.324 entity between the calling H.324 entity and the called H.324 entity, and disconnects the connection between the calling H.324 entity and the broadband resource device.