The present invention provides a data transmission method and a communications device. The communications device includes: a transceiver, configured to send a transmission frame to a second communications device, so that the second communications device acquires data information in the transmission frame, where the transmission frame includes a first part and a second part, the transceiver sends the first part of the transmission frame by using a first quantity of subcarriers, the transceiver sends the second part of the transmission frame by using a second quantity of subcarriers, and the first quantity is not equal to the second quantity; and the transceiver, further configured to perform a next time of information transmission with the second communications device. A throughput can be effectively increased.