The utility model provides a coke cleaning device for a furnace mouth of a smelting furnace. The decoking device comprises a decoking ejector rod and a decoking extension rod, the decoking extension rod is fixedly connected to the top end of the decoking ejector rod; the decoking ejector rod is fixedly connected to the decoking trolley through a decoking base; a fixed bracket is arranged below thedecoking trolley; a sliding rail is arranged on the fixed bracket; the pulley is fixed on a bracket of the decoking trolley through a connecting shaft; wherein a sliding rail is arranged on the decoking trolley, the pulley is connected to the sliding rail in a sliding mode, a hoist fixing frame is arranged above the decoking trolley, the hoist fixing frame is connected with a hoist fixing chain,the hoist fixing chain is connected with a fixing shaft of an electric hoist, and a hinge of the electric hoist is connected to the fixing end of a decoking ejector rod. According to the utility model, mechanical equipment is used for replacing manual operation, so that the labor intensity of staff is greatly reduced, and meanwhile, the hidden danger that personal safety accidents are easy to occur when the staff operates in a high-temperature environment is avoided.