A novel low-voltage reactive compensation device comprises a current transformer, an alternating-current plug-in unit and an A/D converter and is characterized by further comprising a reactive compensation controller, an executing mechanism, an electronic compound switch and a compensation element. The reactive compensation controller is composed of a CPU, an alternating-current module, a power supply module, an outlet module and a man-machine conversation panel. The electronic compound switch is formed by connecting a thyristor and an alternating-current contactor in parallel and fully utilizes the advantage that the switching time of the thyristor is accurate to control, and a thyristor switch is used as a main switch at the switching moment of a capacitor bank and is turned off when capacitors are put into operation, so that load current of the capacitors flows across contacts of the alternating-current contactor. The controller of the novel low-voltage reactive compensation device is designed based on a 16-bit DSP, is high in response speed and can conduct dynamic tracking compensation on a reactive low voltage distribution network. In addition, the novel low-voltage reactive compensation device is simple in control, reliable in performance, friendly in human-computer interface and convenient to operate and is suitable for low-voltage reactive compensation of a power grid.