The invention discloses a safe landing device adopting permanent magnets variable in
magnetic field and magnetorheological fluids variable in area. The safe landing device is characterized by comprising a base, a worm, a worm wheel, winding drums and a deceleration descending device, the worm wheel and the worm are meshed together, the right end of the worm is connected with the winding drums, thedeceleration descending device is located on one side of the worm, and comprises a first shell, a second shell, a screw, a
rotating disc and a moving disc, the two ends of the screw are connected with the first shell and the second shell correspondingly, moreover, the screw is connected with the worm wheel, the
rotating disc is close to the second shell, the moving disc and the screw are meshed together, a sealing ring is arranged between the
rotating disc and the moving disc, the portion among the first shell, the second shell, the rotating disc, the moving disc and the sealing ring is filled with the magnetorheological fluids, and one permanent
magnet is arranged on each of the sides, deviating from each other, of the rotating disc and the moving disc. The safe landing device has the advantages that the structure is simple, the landing distance is large, moreover, adjustment can be performed according to actual conditions, the adaptability is higher, the comfort is good, moreover, the safety is higher, and the stability is better.