The high efficient ball mill produced by our company is designed by adopting good points and avoiding shortcomings based on features of the open-circuit grinding system. Compared to the same size ball mill, in addition to advantages of the open-circuit mill, the capacity has increased a lot, the powder is finer and the specific surface(blaine) is bigger. This ball mill，with features of high capacity and high fineness, is a new type of grinding equipment for producing high quality cement. It has adopted special integrate diaphragm and discharge grate to adjust material levels of every chamber so as to increase air ventilation and improve condition inside mill; Meanwhile, it has also used new type of lining plate, regulated mill rotation speed, optimized gear designing and lubrication parameters of bearing bushes so as to increase its operational stability, service life and grinding efficiency.