The invention relates to a vertical mill achieving automatic deironing. A deironing device and an iron discharging channel are arranged in a grinding cavity. The deironing device is of a crawler beltstructure. The surface of a crawler belt of the deironing device has magnetism. The first end of the deironing device is fixed to the side wall of the grinding cavity, and the second end of the deironing device inclines downwards and is arranged under a discharging opening of a screw conveyor. The iron discharging channel is arranged in a manner of being attached to the side wall of the grinding cavity and extends to the outer portion of a deslagging opening. A scraping plate is arranged on the outer side of the top of the iron discharging channel and is in close contact with the surface of the position, at the first end, of the crawler belt of the deironing device. Effective deironing on powder can be achieved, the purity of the powder can be improved, and the service life of equipment can be prolonged.