The invention discloses a permanent magnetic classificator. The permanent magnetic classificator comprises a main frame, a power frame, a coupler, a speed reducer, a motor, a bearing pedestal, a support seat and a magnetic system adjustment device, also comprises a magnetic cylinder device composed of a magnetic cylinder, a seal cover, a magnetic system, a magnetic system shaft and helical blades, and also comprises a feeding device, an ore washing tank, an ore unloading plate, an ore discharge tank, a concentrate unloading hopper, a tailing unloading hopper, an ore washing water pipe with small water spray drill holes, and an ore unloading water pipe with small water spray drill holes. The helical blades are welded to the outer periphery of the magnetic cylinder. The magnetic system has 360 degrees of a magnetic wrap angle in the magnetic cylinder and has 270 degrees of a magnetic wrap angle close to the concentrate unloading hopper. Permanent magnets of the magnetic system are arranged on a magnet base from left to right in a ladder shape in an NS screw type and form a screw-type magnetic circuit. The permanent magnetic classificator is suitable for a large-scale production flow process, reduces an investment and a cost, can screen iron ores having a good grade, can be operated simply, is light, has a small covering area, saves energy and is convenient for operation and maintenance.