A method, a device, and a conference system for processing a media data packet are provided. The method includes: establishing with a conference proxy server (CPS), a virtual public participant (VPP) channel corresponding to a conference identity; when there are media data packets with same content in a media data packet corresponding to each conference member identity, acquiring a media data packet with a highest frequency of same content among the media data packets as a public media data packet, and forwarding the public media data packet to the CPS through the VPP channel; acquiring a conference member identity that currently does not multiplex the VPP channel, generating a real-time transport protocol control protocol (RTCP) multiplexing start command corresponding to the conference member identity, and delivering the RTCP multiplexing start command to the CPS, so that the CPS starts to forward the public media data packet to a user equipment corresponding to the conference member identity.