The main motor of HGM Three-rings Medium-Speed Micro-powder Grinder drivers spindle and every layer turntable rotating by reducer, through studs, turntable drive dozens of ring roller grinding rolling and rotating in grinding ring roll away. Bulk material was crushed into small particles by hammer crusher, then enter into storage silo by elevator, evenly to the material is sent into the middle of upper turntable by electromagnetic vibrating feeder. Material is scatter to the peripheral edge under the effect of centrifugal force, and fall into the grinding ring roll away, stamping, roll grinding, polishing and crushing by ring rolling. The material is crushed in the first layer then falls into the second and third layer. The pumping action of high pressure centrifugal fan sucked the external air into the machine, and send crushed coarse powder into powder separator through the third layer. The vortex generated by the rotating turbine of powder separator make coarse particulate material down regrinding, powder along with the air go into the cyclone powder collector, and discharge from lower discharge valve, that is finished product, but airflow along with a small amount of fine dust, is purified through pulse dust collector and then discharged from the fan and muffler.