The embodiment of the invention discloses a distributed OFDMA random access method, an AP (access point) and user equipment STA, and the method can effectively reduce the completion conflict rate and effectively shorten the competition access time. According to the invention, the method comprises the steps that the AP calculates a competition window initial value CWini according to the number N of pieces of correlated user equipment STA and the number of RUs (resource units), so as to enable CWini to serve as a dynamically-changing more reasonable competition time window value; the AP broadcasts the CWine, so as to enable the STA correlates with the AP to participate in the competition according to the CWini. Therefore, the CWini serves as the dynamically-changing more reasonable competition time window value, the conflict rate of competition can be effectively reduced, the bandwidth resources can be effectively used, the system throughput can be increased, and the competition access time can be effectively shortened.