A method for producing a sintered R-Iron-Boron (R-Fe-B) magnet, the method comprising: producing a sintered magnet R1-Fe-B-M, wherein R1 is neodymium (Nd), praseodymium (Pr), terbium (Tb), dysprosium (Dy), gadolinium (Gd), holmium (Ho), or a combination thereof, and accounts for 26-33 wt. % of the total weight of the sintered magnet R1-Fe-B-M; M is titanium (Ti), vanadium, chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), gallium (Ga), calcium (Ca), copper (Cu), Zinc (Zn), silicon (Si), aluminum (Al), magnesium (Mg), zirconium (Zr), niobium (Nb), hafnium (Hf), tantalum (Ta), tungsten, molybdenum (Mo), or a combination thereof, and accounts for 0-5 wt. % of the total weight of the sintered magnet R1-Fe-B-M; the boron accounts for 0.5-2 wt. % of the total weight of the sintered magnet R1-Fe-B-M; and the rest is Fe; removing oil, washing using an acid solution, activating, and washing using deionized water the sintered magnet, successively; mixing a superfine terbium powder, an organic solvent, and an antioxidant to yield a homogeneous slurry, coating the homogeneous slurry on a surface of the sintered magnet; and sintering and aging the sintered magnet, wherein: a sintering temperature is between 850 and 970°C, a sintering time is between 5 and 72 h, a sintering pressure is between 10 -3 and 10 -4 Pa, an aging temperature is between 470 and 550°C, and an aging time is between 2 and 5 h, whereby the sintered magnet after sintering and aging has the following property: Hcj 4 − Hcj 1 > 7.96 × 10 5 A / m; Br 1 − Br 4 < 0.02 T; wherein the Hcj represents a coercive force of the sintered magnet obtained in; Hcj represents the coercive force of the sintered magnet obtained in; Br represents a residual magnetism of the sintered magnet obtained in; and Br represents the residual magnetism of the sintered magnet obtained in. producing a sintered magnet R1-Fe-B-M, wherein R1 is neodymium (Nd), praseodymium (Pr), terbium (Tb), dysprosium (Dy), gadolinium (Gd), holmium (Ho), or a combination thereof, and accounts for 26-33 wt. % of the total weight of the sintered magnet R1-Fe-B-M; M is titanium (Ti), vanadium, chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), gallium (Ga), calcium (Ca), copper (Cu), Zinc (Zn), silicon (Si), aluminum (Al), magnesium (Mg), zirconium (Zr), niobium (Nb), hafnium (Hf), tantalum (Ta), tungsten, molybdenum (Mo), or a combination thereof, and accounts for 0-5 wt. % of the total weight of the sintered magnet R1-Fe-B-M; the boron accounts for 0.5-2 wt. % of the total weight of the sintered magnet R1-Fe-B-M; and the rest is Fe; removing oil, washing using an acid solution, activating, and washing using deionized water the sintered magnet, successively; mixing a superfine terbium powder, an organic solvent, and an antioxidant to yield a homogeneous slurry, coating the homogeneous slurry on a surface of the sintered magnet; and sintering and aging the sintered magnet, wherein: a sintering temperature is between 850 and 970°C, a sintering time is between 5 and 72 h, a sintering pressure is between 10 -3 and 10 -4 Pa, an aging temperature is between 470 and 550°C, and an aging time is between 2 and 5 h, whereby the sintered magnet after sintering and aging has the following property: Hcj 4 − Hcj 1 > 7.96 × 10 5 A / m; Br 1 − Br 4 < 0.02 T; wherein the Hcj represents a coercive force of the sintered magnet obtained in; Hcj represents the coercive force of the sintered magnet obtained in; Br represents a residual magnetism of the sintered magnet obtained in; and Br represents the residual magnetism of the sintered magnet obtained in. a sintering temperature is between 850 and 970°C, a sintering time is between 5 and 72 h, a sintering pressure is between 10 -3 and 10 -4 Pa, an aging temperature is between 470 and 550°C, and an aging time is between 2 and 5 h, whereby the sintered magnet after sintering and aging has the following property: Hcj 4 − Hcj 1 > 7.96 × 10 5 A / m; Br 1 − Br 4 < 0.02 T; wherein the Hcj represents a coercive force of the sintered magnet obtained in; Hcj represents the coercive force of the sintered magnet obtained in; Br represents a residual magnetism of the sintered magnet obtained in; and Br represents the residual magnetism of the sintered magnet obtained in.