HSW series micronizer air jet mill, with cyclone separator, dust collector and draft fan to constitute a grinding system. Compressed air after being dried is injected into grinding chamber quickly by the injection of valves. At connection points of big amount of high-pressure air currents, feed materials are collided, rubbed and sheared repeatedly to powders. The grinded materials go into classifying chamber with uprising air flow, under the condition of lashing forces of draught. Under strong centrifugal forces of high-speed rotating turbo wheels, coarse and fine materials are separated. Fine materials in line with size requirements go into cyclone separator and dust collector through classifying wheels, while coarse materials fall down to grinding chamber to be grinded continuously.