The invention provides an automatic control method of small and medium-sized ball mills. According to the automatic control method, an industrial automation control system is established by combiningvarious electrical components to achieve the purposes of site data collection, process control, operating parameter monitoring and equipment protection of the small and medium-sized ball mills, an industrial all-in-one machine and an industrial controller are applied and matched with each other to control the small and medium-sized ball mills and the support equipment of the small and medium-sizedball mills, the visuality is good, the man-machine interaction capacity is high, an industrial all-in-one machine screen can display working conditions and various parameter real-time data of all points of the small and medium-sized ball mills, master data real-time curves, failure warning records and major parameter protection value setting, and the industrial controller is reasonable in controlprocess, comprehensive in protection and capable of fully protecting safe production of the small and medium-sized ball mills.