Abstract: Embodiments of this application provide a data transmission method, a transmit device, and a receive device. The method includes: sending important data of a media data frame to a receive device in a HARQ transmission mode; and after the important data of the media data frame is successfully sent, sending unimportant data of the media data frame to the receive device in a non-HARQ transmission mode. Based on this solution, data of the media data frame is classified into the important data and the unimportant data, and the unimportant data is sent after the important data is successfully sent. In this way, on one hand, the important data is preferentially sent, and successful sending of the important data can be ensured in the HARQ transmission mode.