The invention discloses a low-voltage rectifying device, comprising a switch (1), a three-phase analog voltage transformer (2), a voltage regulator (3) and a boosting transformer (4), wherein an input end of the switch (1) is connected with an AC (alternating current) three-phase 380V power supply; a voltage output end of the switch (1) is connected with a voltage input end of the voltage regulator (3); a voltage output end of the voltage regulator (3) is connected with a voltage input end of the boosting transformer (4); and the three-phase analog voltage transformer (2) is connected with the AC three-phase 380V power supply by the input end of the switch (1). The low-voltage rectifying device can test a DC (direct current) de-icing device conveniently and ensures the normal operation of the DC de-icing device during circuit icing. The low-voltage rectifying device is convenient to move and use for field test, and is simple in structure and operation processes and low in cost.