The invention relates to a preparation method of an aryl propionic acid derivative, comprising the following step of: making a compound expressed by a formula II react according to the following route so as to prepare the aryl propionic acid derivative expressed by a formula I, wherein R1, R2, R3, R4 and R5 independently express hydrogen, alkyl with 1-4 carbon atoms, alkoxy with 1-4 carbon atoms, halogen, trihalogenated methyl and nitryl; R7 and R8 independently express an ester group and a cyano group; R6 expresses carboxyl or a cyano group; X expresses fluorine, chlorine, bromine or iodine; when R7 and R8 both express the ester group or the cyano group, R6 expresses the carboxyl; and when R7 expresses the ester group and R8 expresses the cyano group, R6 expresses the cyano group. The preparation method of the aryl propionic acid derivative has the advantages that raw materials are easy to obtain and low in price, oxidation and reduction reaction are not needed, the route is simple, the reaction condition is moderate, the production equipment requirement is low, a small quantity of the three wastes is discharged and industrialized production can be realized easily, thereby the preparation method can be widely used for synthesizing medicaments, daily chemicals, and the like.