A terminal power-saving method, a terminal power-saving device, and a network-side power-saving device are disclosed. The terminal power-saving device includes a power-saving parameter receiving module and a power-saving execution module. The power-saving parameter receiving module is configured to receive an idle-mode power-saving parameter from a network side, and the power-saving execution module is configured to execute a power-saving operation according to the idle-mode power-saving parameter after the terminal enters an idle mode. When a terminal accessing a 3GPP network has a power-saving requirement, the terminal can perform more optimal power-saving control through a long DRX parameter in a connection mode, and in an idle mode the terminal can receive paging message in an active window time interval and close a wireless transceiver system in a dormant time interval, thereby greatly reducing the power consumption of the terminal, and achieving the purpose of power-saving.