The invention belongs to the field of magnetic material. At present much of the permanent magnet material is thin belt or powder, and since the custom sintering process for preparing block material will make the crystal grow, the magnetic property drops significantly. The steps of said invention comprises: the alloy whose component is RxFeyBz, in which R stands for rare-earth Nd or Pr element and the content of x is 4-10, y is 78-88, z is 6-18, is smelted for mother alloy in induction furnace in vacuum; Then preparing the quenched alloy in amorphous, nanometer crystalline state or amorphous-nanometer mixed state by smelting quick-quench method; the linear speed of smelting quick-quench is arranged between 10-50 m / s; under the protection of inertance gas, abrading the alloy into powder whose coarseness is lower than 80 items; encasing the powder into module to precompression and shaping, while range of pressure is 10-1000MPa; carrying the process of discharging plasma sintering, while the sintering temperature is 550Deg C.-700Deg C., the pressure is 30-1000MPa, the elevated temperature speed is 50-500Deg C. / min, the time of heat preservation is 0-10 min, the elevated temperature speed is 50-200Deg C. / min, Said invention can realize high magnetic property material with high degree of compactness, whose crystal grain is smaller than 100 nanometers, and it can be used in high temperature.