The invention relates to a preparation method of a rare earth permanent magnet. The preparation method comprises the following steps of (1) providing first magnetic powder and second magnetic powder separately, wherein the first magnetic powder is alloy magnetic powder B; the second magnetic powder is alloy magnetic powder R or mixed magnetic powder A; the mixed magnetic powder A is obtained by mixing of the alloy magnetic powder B and alloy powder; the coercivity of a magnet prepared from the second magnetic powder is higher than that of a magnet prepared from the first magnetic powder; (2) putting the first magnetic powder in the middle part of a die, putting the second magnetic powder into the upper part and the lower part of the die, and performing hot press molding to obtain a hot pressed magnet; and (3) performing thermal deformation molding on the hot pressed magnet to obtain the rare earth permanent magnet, wherein the rare earth permanent magnet comprises a middle layer formedby the first magnetic powder and an upper layer and a lower layer formed by the second magnetic powder; and in addition, a transition layer is formed between the middle layer and the upper layer, andbetween the middle layer and the lower layer separately. The invention also relates to a rare earth permanent magnet body.