Manufacturing method for improving sintered NdFeB magnet coercive force

Provided is a manufacturing method for improving sintered NdFeB magnet coercive force. On the basis that the original composition ratio of a sintered NdFeB magnet is not changed, parameters of the rapid hardening process for magnet casting are changed to achieve secondary jet milling so that the average particle size of particles of the magnet can be less than or equal to2.5um, after lower-temperature sintering is controlled between 1020 DEG C and 1035 DEG C for 3.5-5.0 hours, aging treatment is carried out under 450-600 DEG C for 4-6 hours, the powder size of the magnet is lowered after rapid hardening casting and secondary jet milling technologies, surface activity is increased, the particles are easily compacted in a sintered mode, compactness of the magnet can be guaranteed and meanwhile grains can be prevented from rapidly growing up through combination of the lower-temperature sintering, magnetic performance of the magnet is improved, the coercive force is increased by 2-3kOe on average, and the price performance ratio of the magnet is remarkably increased.