The invention discloses a three-step distributed wireless cooperative multicast/broadcast method, which is to acquire spatial diversity gain by using the synchronous cooperation among a plurality of users. In the method, multicast/broadcast is realized by three steps: a first step of source multicast/broadcast for setting time distribution and data rate for each step, a second step of user feedback for allowing a user to use intercepted feedback channel information to analyze the cooperative contribution reasonably, determine if to cooperate and distribute the transmission power, a third stepof user distributed cooperative transmission for allowing a cooperated user to process cooperative data in all paths by using equal-gain combination or maximum ratio combination so as to improve receiving performance. The method improves the effectiveness of cooperative transmission, reduces power consumption and improves the throughput and fairness of multicast.