The present invention discloses a data transmission method, including: receiving N streams of video data uploaded by a video capture terminal, where N is an integer greater than or equal to 1; receiving loopback indication information sent by a mobility management entity or the video capture terminal, where the loopback indication information carries an identifier of a bearer of video data to be looped back; confirming, 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; and sending the video data to be looped back to a trunking terminal. In the data transmission method provided by the embodiments of the present invention, data that the trunking terminal needs to monitor is directly looped back at the base station. Therefore, a transmission delay may be reduced, and video data obtained by video surveillance is transmitted to the trunking terminal in real time.