A backup method for a transmission control protocol module, TCP, connection, comprising: processing a first input packet, and generating, according to a processing result of the first input packet, a new TCP status and a new socket status by a first processing unit in an active board when the first input packet enters a TCP module of the active board; backing up, to a TCP module of a standby board, the TCP status and the socket status that are generated according to the processing result of the first input packet by a first backup unit in the active board; sending, to an application module in the active board, a second input packet generated by means of processing the first input packet by a first sending unit in the active board; receiving a first output packet, by a first receiving unit in the active board, obtained by means of processing the second input packet by the application module in the active board; processing the first output packet, and generating, according to a processing result of the first output packet, a new TCP status and a new socket status by a second processing unit in the active board; and backing up, by a second backup unit in the active board, to the TCP module of the standby board, the TCP status and the socket status that are generated according to the processing result of the first output packet; wherein the backing up, to the TCP module of the standby board, the TCP status and the socket status that are generated according to the processing result of the first input packet comprises: sending, to the TCP module of the standby board, a difference between the TCP status generated according to the processing result of the first input packet and a previous TCP status, and a difference between the socket status generated according to the processing result of the first input packet and a previous socket status; and updating, by the TCP module of the standby board, a TCP status and a socket status on the standby board to the statuses that are generated according to the processing result of the first input packet on the active board after receiving the difference. processing a first input packet, and generating, according to a processing result of the first input packet, a new TCP status and a new socket status by a first processing unit in an active board when the first input packet enters a TCP module of the active board; backing up, to a TCP module of a standby board, the TCP status and the socket status that are generated according to the processing result of the first input packet by a first backup unit in the active board; sending, to an application module in the active board, a second input packet generated by means of processing the first input packet by a first sending unit in the active board; receiving a first output packet, by a first receiving unit in the active board, obtained by means of processing the second input packet by the application module in the active board; processing the first output packet, and generating, according to a processing result of the first output packet, a new TCP status and a new socket status by a second processing unit in the active board; and backing up, by a second backup unit in the active board, to the TCP module of the standby board, the TCP status and the socket status that are generated according to the processing result of the first output packet; wherein the backing up, to the TCP module of the standby board, the TCP status and the socket status that are generated according to the processing result of the first input packet comprises: sending, to the TCP module of the standby board, a difference between the TCP status generated according to the processing result of the first input packet and a previous TCP status, and a difference between the socket status generated according to the processing result of the first input packet and a previous socket status; and updating, by the TCP module of the standby board, a TCP status and a socket status on the standby board to the statuses that are generated according to the processing result of the first input packet on the active board after receiving the difference. sending, to the TCP module of the standby board, a difference between the TCP status generated according to the processing result of the first input packet and a previous TCP status, and a difference between the socket status generated according to the processing result of the first input packet and a previous socket status; and updating, by the TCP module of the standby board, a TCP status and a socket status on the standby board to the statuses that are generated according to the processing result of the first input packet on the active board after receiving the difference.