The embodiment of the invention provides a method, a system and a device thereof for setting up a transmission channel. A transmission bearer corresponding to the base station is set up before the Multimedia Broadcast Multicast Service (MBMS) service is started. When the MBMS service is started, whether a plurality of cells set up transmission bearer does not need to be judged, and transmission bearer does not need to be set up during the starting of the MBMS service. What is needed is to set up the public transmission channel in the cell by using the transmission bearer established in advance, thus simplifying and accelerating the starting of MBMS service; likewise, when the MBMS service ends, whether public transmission channels in other cells in the base station use the transmission bearer does not need to be judged, and the transmission bearer during the ending of the MBMS service does not need to be deleted, thus simplifying and accelerating the ending of MBMS service.