The invention discloses relates to the power supply field, in particular to an auxiliary opening device of an electrical cabinet, which is simple in structure and convenient to operate, and improves the working efficiency. The auxiliary opening device comprises vertical frames, a supporting plate and a vertical ladder, wherein the vertical frames are perpendicularly arranged; a semicircular hoop is connected to one end of each vertical frame through a bolt; the supporting plate is hinged to the other ends of the vertical frames; the vertical ladder is hinged to the end, towards an electric pole, of the supporting plate; a supporting rod is arranged between the supporting plate and the vertical frames; the supporting rod is positioned at the end, away from the electric pole, of the supporting plate; one end of the supporting rod is hinged to the vertical frames; and the other end of the supporting rod is connected to the supporting plate through a bolt. The inferior of the electrical cabinet is connected to the ground through perpendicular stand columns, caulking grooves are formed in the stand columns, and the caulking grooves are used for placing the vertical frames. The auxiliary opening device is convenient to process, and low in cost.