Method for preparing R-Fe-B based sintered magnet

A method for preparing an R—Fe—B based sintered magnet. The method includes : 1) preparing a R1—Fe—B-M alloy, pulverizing the R1—Fe—B-M alloy to yield a R1—Fe—B-M alloy powder, adding a heavy rare earth powder of R2 or R2X and subsequently adding a lubricant to the R1—Fe—B-M alloy powder and uniformly stirring to form a mixture, where R1 being Nd, Pr, Tb, Dy, La, Gd, Ho, or a mixture thereof; M being Ti, V, Cr, Mn, Co, Ga, Cu, Si, Al, Zr, Nb, W, Mo, or a mixture thereof; R2 being at least one from Tb, Dy, and Ho; X being at least one from O, F, and Cl; 2) pressing the mixture obtained in step 1) to form a compact, and sintering the compact in a pressure sintering device in vacuum or in an inactive gas atmosphere to obtain a magnet; and 3) aging the magnet obtained in step 2).