The invention relates to a retaining-plate crank arm lock for a 10KV metal enclosed switch cabinet. The retaining-plate crank arm lock is characterized in that the retaining-plate crank arm lock is provided with a long and thin cylindrical lock body, the lock body is provided with a brake device, a lock cylinder device and a transmission device, the brake device comprises a pressure-bearing spring, a circular metal gasket, a pressure spring, a tap position bolt and a tap position hole, the lock cylinder device comprises an inner rail parallel with a cylinder longitudinal axis, square blocking pins, a lock hole I, a sound and photoelectric device and a transverse retaining plate, the sound and photoelectric device is provided with an indicator lamp, a loudspeaker, a button cell, a wire and positive and negative electrode columns, the transmission device comprises a lock hole II, a metal conduction electrode plate and rail feet, the transmission device is slidably fixed on the inner rail of the lock cylinder device through the rail feet, a connecting shaft and a cuboid rotary shaft are arranged at the tail end of the transmission device, a keyhole is arranged in the middle of the cuboid rotary shaft, a crank arm key is arranged in the keyhole. The retaining-plate crank arm lock using the sound and photoelectric device to give out an alarm is reasonable in structure, capable of being operated by one hand and quite convenient.