A method for maintaining the connection between a terminal and a network server is described. The terminal has a first processing unit with a first state and a second state, wherein the power consumption of the second state is less than the power consumption of the first state. When the first processing unit is in the second state, the terminal or the network server sends heartbeat data packets periodically in order to maintain the connection between said terminal and said network server. During the period that the terminal or the network server sends a periodic heartbeat data packet, a main processor of the terminal will not be woken up Thus, the terminal in a sleep state can maintain connection with the network server, and not be woken up due to the heartbeat data packets sent by the network server, which reduces the power consumption of the terminal.