A method, user equipment (UE) and application server for adding media stream of multimedia session. A UE1 establishes a multimedia session with a UE2, receives a media stream adding request directed at the multimedia session of the UE1; the media stream adding request includes an identity of a UE3 and the media type of the media flow requested to be added; the UE3 is controlled to establish a media stream of the media type with the UE2. Therefore, adding the media stream on the UE3 is realized, and the user may realize the multimedia session with the peer end through multiple UEs, thereby avoiding the inconvenience that the media stream can only be added to the two parties in the session and living up to the users' diversified requirements on the multimedia services.