Model PMG high efficient ball mill has been designed with the merits of open circuit grinding system and important renovations on traditional ball mills. Besides they have all the good advantages of open circuit mills, production capacity has been raised substantially, product becomes super fine and Blains has been increased. It has provided a new type of grinding equipment for producing high strength grade cement with high output and super fineness. Compared with other mills, the output has been increased about 20% and unit product power consumption has been reduced 10%-12% down.