The invention relates to the technical field of bearings, in particular to a variable-stiffness radial permanent magnetic bearing which comprises a radial permanent magnetic bearing inner ring, wherein a radial permanent magnetic bearing outer ring is arranged outside the radial permanent magnetic bearing inner ring and fixed on a rack of equipment; the radial permanent magnetic bearing inner ringis arranged on a rotary main shaft of the equipment; a shaft-end plug is fixed at one end of the rotary main shaft; the radial permanent magnetic bearing inner ring is formed by splicing a pluralityof inner ring blocks; the inner ring blocks are arranged on the shaft-end plug in a conferential array and capable of radially sliding along the shaft-end plug; elastic limiting structures used for preventing the inner ring blocks from sliding off from the shaft-end plug are arranged on the inner ring blocks; both the inner ring blocks and the radial permanent magnetic bearing outer ring are radially magnetized; the magnetized direction of each inner ring blocks and that of the radial permanent magnetic bearing outer ring are opposite; the variable-stiffness radial permanent magnetic bearing constituted by the inner ring blocks and the radial permanent magnetic bearing outer ring serves as a repulsive-force radial bearing; and a gap is left between the inner ring blocks and the radial permanent magnetic bearing outer ring as well as serves as a radial air gap of the variable-stiffness radial permanent magnetic bearing.