The invention relates to a novel power-saving system comprising a hand-held control terminal, a power-saving device, a remote communication unit, and a data management unit. The hand-held control terminal sets the reference value of voltage and the reference value of current. A sampling module detects load voltage and load current and sends the load voltage and the load current to a control circuit in the power-saving device. The control circuit analyzes a circuit detection signal and a reference signal and sends a regulating signal to a voltage-regulating device of the power-saving device when the circuit detection signal and the reference signal have a certain deviation in order to correspondingly regulate output voltage until the output voltage satisfies a requirement. The remote communication unit may remotely communicate with the power-saving device and receives data. The data is stored and processed by the data management unit or is remotely sent to a corresponding module in the power-saving device by a command given by a technical worker in order to change the operation of the system. The power-saving system is low in operating capacity, low in transformer weight, high in anti-interference capability, high in reliability and stability of a bypass protection circuit, low in power consumption, and capable of being remotely regulated and controlled and storing data.