Method and apparatus for transmitting retransmission protocol data unit (PDU) by radio link control layer

The invention discloses a method and an apparatus for transmitting a retransmission protocol data unit (PDU) by a radio link control layer, belonging to the technical field of communication, to improve the efficiency of transmitting the retransmission PDU, so as to improve the overall speed of a business. The method for transmitting the retransmission PDU by the radio link control layer comprises the steps that a retransmission data frame which independently consists of the retransmission PDU is formed by a radio network control (RNC), wherein the retransmission data frame includes retransmission indication information which is used for indicating for a base station that the data frame is a retransmission data frame used for transmitting the retransmission PDU; and the retransmission data frame is sent to the base station by the RNC.