A data transmission method is disclosed. N streams of video data uploaded by a video capture terminal are received, where N is an integer greater than or equal to 1; loopback indication information sent by a mobility management entity or the video capture terminal is received, where the loopback indication information carries an identifier of a bearer of video data to be looped back; according to the identifier of the bearer of the video data to be looped back, the video data to be looped back corresponding to the identifier of the bearer of the video data to be looped back is confirmed; and the video data to be looped back is sent to a trunking terminal. In the data transmission method, data that the trunking terminal needs to monitor is directly looped back at the base station.