Abstract: A method and an apparatus is disclosed for retransmitting Code Blocks, the method includes sending a control command and a Transport Block to a second device by a first device. The Transport Block includes at least one Code Block Group which is a basic unit for sending the Transport Block. The method also includes receiving a feedback character of Hybrid Automatic Repeat request corresponding to each of the Code Block Groups in the Transport Block sent from the second device by the first device and if at least one of the feedback characters of Hybrid Automatic Repeat request indicates that at least one of the Code Block Groups is not received successfully, the first device retransmits a Transport Block containing the at least one unsuccessfully-received Code Block Group to the second device, and the first device sends a corresponding control signal for the second device to identify the at least one Code Block Group retransmitted.