The main component of wet overflow ball mill is a cylinder with bigger diameter and smaller length which is revolved by transmitting machinery. Materials are put in cylinder through the feed opening and then thoroughly grinded. The falling course of iron balls and ores can produce huge falling impact and autogenous grinding. The continuous feeding of ores can create considerable pressure to make ores move from feed opening toward discharge opening. Finally, acceptable particles are discharged from the discharge opening. Hollow shaft with the anti-spiral blade returns the steel ball and the coarse ore block. Wet type overflow ball mill works for fine fineness grinding.