A data transmission method, comprising: sending, by a cellular access device, non-cellular access device addition request information to a non-cellular access device, wherein the non-cellular access device addition request information is used to instruct the non-cellular access device to allocate a resource of a non-cellular network for a terminal, the non-cellular access device addition request information comprises a to-be-added-bearer list, and the to-be-added-bearer list comprises a data radio bearer identifier, DRB ID and an evolved universal terrestrial radio access network radio access bearer identifier, ERAB ID, wherein the DRB ID carried in uplink data is used by the non-cellular access device for finding the ERAB ID which is corresponding to the terminal for uplink data transmission and the non-cellular access device uses the ERAB ID to find an uplink tunnel endpoint identifier, TEID, where the uplink tunnel endpoint is used to indicate a data transmission destination in data transmission; receiving, by the cellular access device, non-cellular access device addition response information from the non-cellular access device, wherein the non-cellular access device addition response information comprises a downlink tunnel endpoint allocated for a bearer to which data of the terminal belongs, the downlink tunnel endpoint comprises a downlink tunnel endpoint identifier, TEID, and a downlink transport layer address, and the downlink tunnel endpoint is used to indicate a data transmission destination in a downlink data transmission path; and, receiving, by the cellular access device, the uplink data from the terminal through the non-cellular access device, the uplink data comprises a LWAAP PDU, the LWAAP PDU comprises the DRB ID. sending, by a cellular access device, non-cellular access device addition request information to a non-cellular access device, wherein the non-cellular access device addition request information is used to instruct the non-cellular access device to allocate a resource of a non-cellular network for a terminal, the non-cellular access device addition request information comprises a to-be-added-bearer list, and the to-be-added-bearer list comprises a data radio bearer identifier, DRB ID and an evolved universal terrestrial radio access network radio access bearer identifier, ERAB ID, wherein the DRB ID carried in uplink data is used by the non-cellular access device for finding the ERAB ID which is corresponding to the terminal for uplink data transmission and the non-cellular access device uses the ERAB ID to find an uplink tunnel endpoint identifier, TEID, where the uplink tunnel endpoint is used to indicate a data transmission destination in data transmission; receiving, by the cellular access device, non-cellular access device addition response information from the non-cellular access device, wherein the non-cellular access device addition response information comprises a downlink tunnel endpoint allocated for a bearer to which data of the terminal belongs, the downlink tunnel endpoint comprises a downlink tunnel endpoint identifier, TEID, and a downlink transport layer address, and the downlink tunnel endpoint is used to indicate a data transmission destination in a downlink data transmission path; and, receiving, by the cellular access device, the uplink data from the terminal through the non-cellular access device, the uplink data comprises a LWAAP PDU, the LWAAP PDU comprises the DRB ID.