The present invention provides a data transmission method. In the method of the present invention, a station receives an indication frame sent by an access point, where the indication frame is used for allocating a designated random contention channel; a channel state of the designated random contention channel is sensed according to the indication frame; and the station sends data on the designated random contention channel after it is detected that the designated random contention channel is in an idle state. Because in the method of the present invention, a designated random contention channel is allocated to a station, the station can send data on the designated random contention channel, contention among stations is reduced and a time for a station to be connected to a random contention channel is reduced.