The present invention provides a multichannel multiple access method based on asymmetric bandwidth and relates to the communication technology field. An AP (Access Point) performs channel competition on a special main channel, and after the AP competition channel is successful, the downlink data business scheduling transmission, the uplink data business scheduling transmission or the uplink data business transmission request collection is selected according to the requirement of the downlink data business. The multichannel multiple access method based on the asymmetric bandwidth fully employs the AP scheduling capacity, the AP has a full-channel monitoring and data transmit-receive capacity, and the STA only has the 20MHz single-channel monitoring and OFDMA sub-channel data transmit-receive capacity and fully utilizes the AP scheduling capacity to ensure that all the channels have more users to transmit and receive the data at the same time so as to greatly improve the MAC efficiency.