Abstract: Disclosed are an acylphosphine oxide compound and a preparation method therefor, which belong to the field of initiators. The method comprises: reacting compound B and compound C under the conditions of an organic base and an organic solvent so as to obtain the acylphosphine oxide compound. The chemical structural formula of compound B is as follows: the chemical structural formula of compound C is as follows: and the chemical structural formula of the acyl phosphine oxide compound is as follows: wherein R1 is hydrogen, a C1-C6 alkyl group, methoxy, methylthio, dimethylamino, chloroformyl, phenyl, benzoyl, (4-dimethylamino) phenyl, ?-naphthyl, ?-naphthyl or (9-ethyl-9H-carbazole)-3-yl, R2 and R1 are the same, n is the substitution number of R1 on the corresponding phenyl ring, and is 1, 2 or 3, and m is the substitution number of R2 on the corresponding phenyl ring, and is 1, 2 or 3. The preparation method is safe and environmentally friendly, and has a high yield.