The invention relates to a strong magnetic variation gradient magnetic separator of an inner permanent magnet cylinder, belonging to the mineral machinery. The strong magnetic variation gradient magnetic separator of the inner permanent magnet cylinder comprises a permanent magnet roller, a control cabinet, an excitation body, a tilt adjusting screw rod of the magnetic separator, a frame, a material discharge box, a material discharging quantity control shutter, a material discharge roller, a roller support idler wheel, an inner bracket beam, a material discharge groove, a bracket, an anti-skid flange plate for the permanent magnet roller, a power motor, an excitation body moving screw rod, and the like. The strong magnetic variation gradient magnetic separator of the inner permanent magnet cylinder has functions of strengthening magnetic field intensity and changing magnetic field gradient, and can further enhance the grade and the yield of the magnetic separation of low magnetic susceptibility mineral power which is difficult to select. The strong magnetic variation gradient magnetic separator has the advantages of compact structure, and convenience for installation and operation, and is suitable for separating various kinds of weak magnetic rare metal mineral powders or exhausting impurities and purifying nonmetal mineral powders. The strong magnetic variation gradient magnetic separator can be separately applied to a dry separation technology or a wet separation technology, and is a permanent magnet high-gradient technical device which can replace an electromagnetic separator with high energy consumption and high gradient.