The granularity of materials is not larger than 12mm,through variable frequency main engine to control charge-in materials quantity. With suitable flow run into grinding chamber.materials in grinding chamber through the hammerblow of hammer and cotter,pelleting materials after grinding flies to round sieve and impinges on the round sieve that makes pelleting materials further grind. At the same time,mutual friction occurs between materials,so mirco fine pellet produced, This grinder is suitable for dry grinding, grind the brittleness,oiliness and heat sensitivity materials need special treatment.