The invention provides a user side low-voltage reactive power compensation device. The device is arranged between a main station and medium-low-voltage grid primary equipment. The device comprises a dual-core processor, a collector, a state quantity measurer, a video converter, mass storage equipment and a relay protection device, wherein the dual-core processor respectively receives voltage and current signals of the medium-low-voltage grid primary equipment collected by the collector, the state quantity of the medium-low-voltage grid primary equipment collected by the state quantity measurer and the digital video converted by the video converter, then performs data processing and transmits to the power distribution network main station, and controls capacitor banks of the low-voltage grid to realize the reactive power compensation; and when the device is in fault, the relay protection device is used for protecting the low-voltage reactive power compensation device. Through adding various functions such as video real-time monitoring, mass storage, high-speed communication into the conventional reactive power compensation device, the problems can be effectively solved, so that the state monitoring capability of electrical equipment is improved, and the accident hidden danger checking level of the electrical equipment is improved.