A heterodimer molecule based on CH3, and a preparation method therefor and a use thereof. By comprehensively considering various interactions between molecules, for example, an ionic action, a hydrophobic interaction and a spatial action, a preferred Fc mutant sequence being more inclined to form a heterodimer rather than a homodimer is screened, and accordingly, the yield of the heterodimer molecule is greatly improved, thereby creating conditions for the preparation of bispecific molecules and the like.