The invention provides a remote on-off control system, which comprises a user computer, a remote computer, a USB cable and a signal processing device, wherein the remote computer comprises a USB interface; the signal processing device comprises an ATX power supply, an ATX power supply interface, an on-off control circuit and a USB interface; the signal processing device is supplied with power by using the ATX power supply; and the remote computer and the signal processing device are connected together through the USB cable. According to the technical scheme of the invention, the remote computer receives remote wakeup command or system closing command from the user computer and executes the corresponding operation according to the remote wakeup command or the system closing command, so thesystem achieves the effect of remote on and off, can realize remote on-off control of non-computer system equipment such as the signal processing device without using a special remote control commandreceiving device and saves energy.