A method for channel content alternation notification and channel re-detecting is provided. The method is: a base station determines that the configured carried content of multimedia broadcast multicast service (MBMS) point to multipoint control channel (MCCH) is altered, and transmits the notification about alternation of the carried content of MCCH to a terminal through a physical downlink control channel (PDCCH); the terminal re-detects MCCH according to the notification after the terminal received the notification. A system and a device for channel re-detecting are provided. The terminal can recognize whether the carried content of MCCH is altered, and re-detect MCCH in case of altered without re-detecting MCCH periodically, therefore it is beneficial to save the resources of terminal.