A hybrid automatic repeat request, HARQ, technology-based communication method, wherein the method comprises: generating, by a first device, at least one transmission indicator and data of at least one second device, wherein the at least one transmission indicator is used to indicate that the data of the at least one second device is retransmitted data or new transmitted data, and the at least one transmission indicator is in a one-to-one correspondence with the data of the at least one second device; and sending, by the first device, the at least one transmission indicator and the data of the at least one second device to the at least one second device, wherein the sending comprises: sending, by the first device, a first physical layer protocol data unit, PPDU, to the at least one second device, wherein the first PPDU comprises the at least one transmission indicator and the data of the at least one second device, wherein the first PPDU comprises a plurality of media access control protocol data units, MPDUs, a first MPDU in the plurality of MPDUs is configured to carry a transmission indicator of the second device, and an MPDU other than the first MPDU in the plurality of MPDUs is configured to carry data of the second device, wherein the first MPDU carrying the at least one transmission indicator and the MPDU other than the first PDU carrying the data are sent using different modulation and coding schemes, MCSs; and when the transmission indicator of the second device is used to indicate that the data of the second device is retransmitted data, the first MPDU further carries HARQ information required by the second device for combining the data, wherein the retransmitted data is sent using the same MCS of a new transmission. generating, by a first device, at least one transmission indicator and data of at least one second device, wherein the at least one transmission indicator is used to indicate that the data of the at least one second device is retransmitted data or new transmitted data, and the at least one transmission indicator is in a one-to-one correspondence with the data of the at least one second device; and sending, by the first device, the at least one transmission indicator and the data of the at least one second device to the at least one second device, wherein the sending comprises: sending, by the first device, a first physical layer protocol data unit, PPDU, to the at least one second device, wherein the first PPDU comprises the at least one transmission indicator and the data of the at least one second device, wherein the first PPDU comprises a plurality of media access control protocol data units, MPDUs, a first MPDU in the plurality of MPDUs is configured to carry a transmission indicator of the second device, and an MPDU other than the first MPDU in the plurality of MPDUs is configured to carry data of the second device, wherein the first MPDU carrying the at least one transmission indicator and the MPDU other than the first PDU carrying the data are sent using different modulation and coding schemes, MCSs; and when the transmission indicator of the second device is used to indicate that the data of the second device is retransmitted data, the first MPDU further carries HARQ information required by the second device for combining the data, wherein the retransmitted data is sent using the same MCS of a new transmission. sending, by the first device, a first physical layer protocol data unit, PPDU, to the at least one second device, wherein the first PPDU comprises the at least one transmission indicator and the data of the at least one second device, wherein the first PPDU comprises a plurality of media access control protocol data units, MPDUs, a first MPDU in the plurality of MPDUs is configured to carry a transmission indicator of the second device, and an MPDU other than the first MPDU in the plurality of MPDUs is configured to carry data of the second device, wherein the first MPDU carrying the at least one transmission indicator and the MPDU other than the first PDU carrying the data are sent using different modulation and coding schemes, MCSs; and when the transmission indicator of the second device is used to indicate that the data of the second device is retransmitted data, the first MPDU further carries HARQ information required by the second device for combining the data, wherein the retransmitted data is sent using the same MCS of a new transmission.