A data transmission method includes sending, by a master station (STA), a request to send (RTX) to an access point (AP) in a same basic service set (BSS), which includes the AP and multiple STAs, and the master STA is a STA that is the first to obtain a channel by contention in the multiple STAs, instructing a surrounding STA to determine, according to conditions, whether to follow the master STA to send an RTX, where a STA following the master STA to send the RTX satisfies conditions that the STA has buffer data to be transmitted, the STA is in the same BSS as the master STA, and a power of a signal received from the master STA is greater than a preset threshold, and receiving response information from the AP to transmit uplink data on a specified sub-channel.