The embodiment of the invention discloses a data transmission method and a base station. The transmission delay of uplink feedback packets is shortened, the downlink sensing rate of the user under TCPtransmission is improved, and the user experience is improved. The method disclosed by the embodiment of the invention comprises the following steps: the base station judges whether a target TCP datapacket sent by the base station is successfully received by a terminal according to a preset mapping relation between the TCP data packet and an RLC PDU; if the target TCP data packet is successfullyreceived, the base station predicts a TCP acknowledgement character ACK corresponding to the target TCP data packet of the terminal is generated, wherein the TCP ACK indicates the acknowledgement that the terminal successfully receives the target TCP data packet sent by the base station; and the base station sends uplink scheduling grant UL grant to the terminal according to the TCP ACK.