A method for implementing coordinated multipoint (CoMP) downlink transmission between base stations, and corresponding base stations. The method comprises: a base station sending signalling to a UE which supports CA and determines to use a CoMP manner to conduct downlink transmission, to instruct the UE to set a HARQ process of an unused CA auxiliary carrier as CA primary carrier data transmission; and when the base station determines that CoMP coordinated neighbouring cells of the UE comprise neighbouring cells with the same frequency under other base stations, scheduling downlink data of the UE in advance in the HARQ process of a primary cell and sending the downlink data and time-frequency resource information thereabout to the neighbouring cells with the same frequency under other base stations, to conduct CoMP downlink transmission. By means of the technical solution, by scheduling a HARQ process of a CA auxiliary carrier by a primary cell in advance and multiplexing same, the elimination of same-frequen
