The invention discloses an automobile air conditioner air duct with a dust removal function. The air duct comprises an air duct body, a dust removal casing is fixedly connected to an opening of the top of the air duct body, a motor mounting base is fixedly connected to the portion, located at the left side of the dust removal casing, of the top of the air duct body, a driving motor is fixedly connected to the top of the motor mounting base, and a driving rotating shaft is fixedly connected to an output shaft of the driving motor. Through the arrangement and cooperation of the dust removal casing, the motor mounting base, the driving motor, the driving rotating shaft, a driving gear, rolling bearings, a threaded rod, a driven gear, a sliding block, a threaded groove and a dust removal plate, the dust removal function is achieved; when tiny dust in air can enter the air duct from an air outlet, the dust is prevented from entering an air conditioner, and therefore the situation that cooling and heat dissipation are seriously affected by the dust is avoided; the service life of the automobile air conditioner is prolonged, the time and labor during cleaning are saved, and great convenience is brought to a user.