With the development of electronic information and network technology, China's surveillance system have made considerable progress on technical and practical application level. Unity has become the common goal of all kinds of video surveillance systems in order to be applied to all areas of society. This paper analyzes the existing interconnection problems in video surveillance system, studies the non-SIP domain and SIP domain protocol carefully, and proposes a generic SIP gateway solutions. We introduce the details of protocol conversion from several aspects such as system registry, directory access and video access. Using our SIP gateway can solve the interconnection issue between non-SIP domain and SIP domain in video surveillance system.