The utility model provides a user side low-voltage reactive power compensation device, which is arranged between a main station and medium-low-voltage grid primary equipment and comprises a dual-core processor, a collector, a state quantity measurer, a video converter and a mass-storage device, wherein the dual-core processor after connected with the mass-memory device respectively communicates with the collector, the state quantity measurer and the video converter through buses, and the dual-core processor is connected with a capacitor group of a medium-low-voltage grid through buses. The user side low-voltage reactive power compensation device can be configured flexibly. Through combination of different-type plate components, a conventional low-voltage reactive power compensation device and a multifunctional user side low-voltage reactive power compensation device can be realized.