Data transmission method and apparatus

Provided is a data transmission method for improving the network transmission performance, comprising: a sending device receiving a state report, wherein the state report comprises first identifiers of lost data packets and the number of the lost data packets, the first identifiers of the lost data packets comprise sequence numbers of the lost data packets, and the sequence numbers comprise sequence numbers that can be recognized by a wireless local area network (WLAN) access device; the sending device determining the lost data packets according to the number of the lost data packets and the first identifiers of the lost data packets; and the sending device retransmitting the lost data packets. In this way, a WLAN access device can parse a sequence number of a received data packet, so that a sequence number of a lost data packet between a sending device and the WLAN access device can be determined; the WLAN access device feeds the sequence number of the lost data packet back to the sending device; and when receiving the sequence number of the lost data packet, the sending device retransmits the lost data packet, thereby reducing the packet loss rate of a data packet and improving the network transmission performance.