A method and a device for transmitting a multimedia broadcast multicast service are provided. The method includes one or more base stations encode and modulate the original multimedia broadcast multicast service data to be transmitted, and transmit the encoded and modulated multimedia broadcast multicast service data to one or more transparent relay stations belonging to the one or more base stations via a specified same time and frequency resource; the one or more transparent relay stations performs a relay process for the received multimedia broadcast multicast service data; then the one or more transparent relay stations and the one or more base stations transmit the multimedia broadcast multicast service data via the specified same time frequency resource simultaneously; and a terminal processes the received multimedia broadcast multicast service data to acquire the original multimedia broadcast multicast service data. The present invention can improve the MBMS service transmission performance in the next generation mobile communication system.