The present disclosure relates to data transmission methods and communications devices. One example communications device includes a transceiver. The transceiver is configured to send a transmission frame to a second communications device, where the second communications device acquires data information in the transmission frame, and the transmission frame includes a first part and a second part. The transceiver is configured to send the first part of the transmission frame by using a first quantity of subcarriers. The transceiver is configured to send the second part of the transmission frame by using a second quantity of subcarriers, where the first quantity is not equal to the second quantity. The transceiver is further configured to perform a next time of information transmission with the second communications device.