Sintered mixed rare earth permanent magnet with high magnetic energy product and preparation method thereof

The invention discloses a sintered mixed rare earth permanent magnet with high magnetic energy product and a preparation method thereof. According to the sintered mixed rare earth permanent magnet, RE2Fe14B (RE comprises one or more of La, Ce, Pr and Nd) compound crystal grains serve as a main phase, a low-melting-point Ce3Ga phase and a low-melting-point MM-rich phase between the crystal grains serve as grain boundary phases, the sintered mixed rare earth permanent magnet contains inevitable impurities, the sintered mixed rare earth permanent magnet comprises the following components in percentage by mass: MMaNdbBcGdTeFe and the balance, and the material does not contain a high-melting-point CeFe2 phase and a CeO2 phase; a, b, c, d and e are numerical values obtained by multiplying the mass percent (wt%) of all the elements in the sintered mixed rare earth permanent magnet by 100, the sintered mixed rare earth permanent magnet with low cost and adjustable magnetic energy product between 40 MGOe and 50 MGOe i