A method for producing a sintered magnet, the method consisting of: 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 27-34 wt. % of a total weight of the sintered magnet R1-Fe-B-M; the boron (B) accounts for 0.8-1.3 wt. % of the total weight of the sintered magnet R1-Fe-B-M; M is titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), gallium (Ga), copper (Cu), silicon (Si), aluminum (Al), zirconium (Zr), niobium (Nb), tungsten (W), molybdenum (Mo), or a combination thereof, and accounts for 0-5 wt. % of the total weight of the sintered magnet R1-Fe-B-M; and the rest is Fe; washing the sintered magnet using an acid solution and deionized water, successively, and drying the sintered magnet to yield a treated magnet; mixing a heavy rare earth element powder RX, an organic solid powder EP and an organic solvent ETto yield a slurry RXE, coating the slurry RXE on a surface of the treated magnet, and drying the treated magnet to yield a treatment unit comprising an RXE layer, wherein the organic solvent ET is ether, benzene, ethyl alcohol, glycerol, ethanediol, or a combination thereof; and heating the treatment unit in at a temperature of between 850°C and 970°C for between 0.5 and 48 hrs, quenching the treatment unit, and then aging the treatment unit at a temperature of between 430°C and 650°C for between 2 and 10 hrs; characterized in that in , the heavy rare earth element powder RX is Dy powder, Tb powder, or a combination thereof; and the organic solid powder EP is a rosin-modified alkyd resin, a thermoplastic phenolic resin, an urea-formaldehyde resin, or a combination thereof. 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 27-34 wt. % of a total weight of the sintered magnet R1-Fe-B-M; the boron (B) accounts for 0.8-1.3 wt. % of the total weight of the sintered magnet R1-Fe-B-M; M is titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), gallium (Ga), copper (Cu), silicon (Si), aluminum (Al), zirconium (Zr), niobium (Nb), tungsten (W), molybdenum (Mo), or a combination thereof, and accounts for 0-5 wt. % of the total weight of the sintered magnet R1-Fe-B-M; and the rest is Fe; washing the sintered magnet using an acid solution and deionized water, successively, and drying the sintered magnet to yield a treated magnet; mixing a heavy rare earth element powder RX, an organic solid powder EP and an organic solvent ETto yield a slurry RXE, coating the slurry RXE on a surface of the treated magnet, and drying the treated magnet to yield a treatment unit comprising an RXE layer, wherein the organic solvent ET is ether, benzene, ethyl alcohol, glycerol, ethanediol, or a combination thereof; and heating the treatment unit in at a temperature of between 850°C and 970°C for between 0.5 and 48 hrs, quenching the treatment unit, and then aging the treatment unit at a temperature of between 430°C and 650°C for between 2 and 10 hrs; <EOS>