The invention discloses a method and a system for realizing mosaic television services, comprising the steps that a headed encoding module generates a sub-channel media stream corresponding to a main-channel media stream, and sends the sub-channel media stream to a channel management module for management; after receiving a mosaic service request, a sub-channel media stream management module sends a sub-channel media stream distribution request to the channel management module; the channel management module sends the sub-channel media stream to a mosaic service management module for processing; and a decoding module decodes the processed sub-channel media stream, generates a mosaic television output signal, and sends the signal to a display module for display. The technical scheme in the present invention can realize mosaic television services in an IPTV (internet protocol television) system simply and flexibly.