The invention discloses a low-voltage automatic continuous adjustable filtering reactive power compensation device, belonging to the technical field of the reactive power compensation of a power grid. The reactive power compensation device uses an adjustable reactor formed by serially connecting an inductance at the rear of a single phase capacitor and a current limiting reactor formed by serially connecting a current limiting inductance in the front of the capacitor as compensation components, the compensation components are respectively electrically connected with a zero load controller, a PLC (programmable logic controller) and a power factor transmitter with switching component J1-J4 relays; and a silicon controlled voltage regulator adjusts the adjustable reactor according to the instruction of the PLC to realize an automatic control power factor within the range of 0.95-0.99. The invention has a function of restraining a harmonic wave and is applied to the places with a higher harmonic wave and a larger impulse current. The device takes a PLC control circuit as a core to ensure the stability of the power factor. By utilizing a composite switch as a switching device of a capacitor bank, the power grid can be ensured to have a higher power factor, the line loss can be reduced and the electric energy quality can be improved.