A data transmission method, comprising: sending, by user equipment, UE, uplink data to a network side device; and processing, by the UE according to feedback information for the uplink data and received from the network side device, a buffer status report, BSR, corresponding to the uplink data or a scheduling request, SR, corresponding to the uplink data; characterized in that after the sending, by UE, uplink data to a network side device, the method further comprises: retaining the BSR; and the processing, by the UE according to feedback information for the uplink data and received from the network side device, a BSR corresponding to the uplink data comprises: when the feedback information indicates that the network side device correctly receives the uplink data, canceling, by the UE, the retained BSR; and when the feedback information indicates that the network side device does not correctly receive the uplink data, continuing, by the UE, retaining the BSR, and triggering SR reporting, wherein the uplink data comprises: a BSR control information element; all to-be-transmitted data in a buffer; or a part of to-be-transmitted data in a buffer, and the BSR; wherein before the sending, by UE, uplink data to a network side device, the method comprises: triggering SR reporting according to the BSR; and receiving an uplink grant corresponding to the SR; and the sending, by UE, uplink data to a network side device comprises: sending the uplink data to the network side device according to the uplink grant. sending, by user equipment, UE, uplink data to a network side device; and processing, by the UE according to feedback information for the uplink data and received from the network side device, a buffer status report, BSR, corresponding to the uplink data or a scheduling request, SR, corresponding to the uplink data; characterized in that after the sending, by UE, uplink data to a network side device, the method further comprises: retaining the BSR; and the processing, by the UE according to feedback information for the uplink data and received from the network side device, a BSR corresponding to the uplink data comprises: when the feedback information indicates that the network side device correctly receives the uplink data, canceling, by the UE, the retained BSR; and when the feedback information indicates that the network side device does not correctly receive the uplink data, continuing, by the UE, retaining the BSR, and triggering SR reporting, retaining the BSR; and the processing, by the UE according to feedback information for the uplink data and received from the network side device, a BSR corresponding to the uplink data comprises: when the feedback information indicates that the network side device correctly receives the uplink data, canceling, by the UE, the retained BSR; and when the feedback information indicates that the network side device does not correctly receive the uplink data, continuing, by the UE, retaining the BSR, and triggering SR reporting, when the feedback information indicates that the network side device correctly receives the uplink data, canceling, by the UE, the retained BSR; and when the feedback information indicates that the network side device does not correctly receive the uplink data, continuing, by the UE, retaining the BSR, and triggering SR reporting, wherein the uplink data comprises: a BSR control information element; all to-be-transmitted data in a buffer; or a part of to-be-transmitted data in a buffer, and the BSR; a BSR control information element; all to-be-transmitted data in a buffer; or a part of to-be-transmitted data in a buffer, and the BSR; wherein before the sending, by UE, uplink data to a network side device, the method comprises: triggering SR reporting according to the BSR; and receiving an uplink grant corresponding to the SR; and triggering SR reporting according to the BSR; and receiving an uplink grant corresponding to the SR; and the sending, by UE, uplink data to a network side device comprises: sending the uplink data to the network side device according to the uplink grant.