In recent years, with the user's requirements on the audio and video communications quality being higher, WebRTC has been widely used for its powerful multimedia processing capabilities. WebRTC only provide a kind of weak signaling JSEP, but enterprise-class converged communications applications must be combination of WebRTC and the actual signaling protocol. SIP protocol is the core technology of IMS, which plays a very important role in the control of multimedia conversation. This paper introduces the existing schemes of WebRTC and SIP protocol integration, studies the problems of WebRTC and SIP protocol integration, and presents a scheme of converged communications of combining WebRTC PeerConnection and SIP protocol based on clients. This study also compares the advantages and the disadvantages of this scheme with other schemes.