The utility model discloses a magnesite is permanent magnetism high gradient magnetic separator for deironing can carry out the desorption to strong magnetic mineral in the magnesite and weak magnetic mineral simultaneously. This magnet separator includes: it is drive arrangement that permanent magnet system, high gradient select separately ring, main shaft, magnetism, unload ore deposit roller brush drive arrangement, select separately the cell body, unload ore deposit roller brush, wash tub pipe, ore discharge water pipe, frame, give mine mouth, magnesite concentrate mouth and impurity tailing mouth. The utility model discloses a neodymium iron boron is as magnetically hard material, electrician's pure iron is as magnetic materials, the magnetic conduction stainless steel is as gathering the magnetism material, application double focusing magnetism technique substep gathers magnetism, the background magnetic field intensity that can make this magnet separator reaches 1.0 -1.5T, actual intensity of working magnetization reaches 1.8 -2.5T, the highest 80mTmm of magnetic field gradient, can carry out the desorption to strong magnetic mineral in the magnesite and weak magnetic mineral simultaneously, reduce the iron in the magnesite to below 0.24%, a technological process is simplified, make the deironing cost reduce by a wide margin.