The invention discloses a motor drainage cooling fan which comprises a bottom plate, fan blades and a guide sleeve. The bottom plate is installed on a rotor of the motor and is in front of the motor.An inverter is located in front of the bottom plate, and the motor is located at one side of an engine. The fan blades are orderly distributed at the periphery of the bottom plate in an annular array.The guide sleeve is concentrically arranged on the outside of the bottom plate, and ends of the fan blades are connected to the inner wall of the guide sleeve. The middle of the bottom plate is provided with a shaft hole. The bottom plate is provided with mounting holes distributed at the periphery of the shaft hole in an annular array. Through the above mode, according to the motor drainage cooling fan, the fan sucks cooling air and the fan blades rotate, the cooling air is centrifuged to the periphery and is led to the motor through the guide sleeve, the cooling air which is centrifuged andpressurized by the fan fully cools the rotor and a stator of the motor, the cooling air which cools the motor continues to pass a motor front end cover to blow the engine, and the engine is cooled.