The utility model relates to a low-voltage compensation device suitable for a ferro silicon smelting mine heating furnace, mainly comprising a mine heating furnace power supply main loop and a compensation loop, wherein the mine heating furnace power supply main loop is formed by that: an electric network high-voltage 110KV loop is accessed to a furnace transformer, the furnace transformer outputs 90-240V low-voltage electric energy, the low-voltage electric energy is accessed to a three-phase electrode through a furnace short network and a furnace water-cooling cable and then sent to a mine heating furnace hearth to perform the smelting production; the compensation loop is formed by that: the compensation loop is led out and welded on a three-phase electrode conductive copper pipe, and then accessed to a compensation main circuit switch through a compensation water-cooling cable and a compensation short network and the compensation main circuit switch is connected with a parallel capacitor set. The voltage loss of the mine heating furnace loop short network is reduced, thus the voltage on the electrode work end is increased and the power factor and the reactive power are also increased.