Method for improving performance of sintered neodymium-iron-boron magnet

The invention discloses a method for improving the performance of a sintered neodymium-iron-boron magnet. The method comprises the following steps: a, sintering a neodymium-iron-boron semi-finished product by adopting a traditional neodymium-iron-boron sintering process; b, adding rare earth powder and an organic solvent into the treatment pond, and stirring to be uniform, a rare earth solution with the concentration being 5-15% is prepared, wherein the rare earth powder is RxFy powder, and R is one or more of heavy rare earth Tb, Dy and Ho; c, soaking the neodymium iron boron semi-finished product prepared in the step a in the rare earth solution in the treatment pond for more than 30 seconds; and d, enabling the to-be-treated product treated in the step c to be subjected to primary tempering for 3-15 h at the temperature of 800-950 DEG C and then subjected to secondary tempering for 3-6 h at the temperature of 450-650 DEG C, and obtaining the final neodymium-iron-boron magnet. Treatment is carried out after