Provided are a 4-cyano-5-(3-indolyl) oxazole compound and a preparation method thereof. 3- (1H-indole-3-group)-3-oxy propionitrile and benzylamine are used as raw materials, and 5-(3-indole) oxazole is a heterocyclic skeleton. The formula is as shown in the description, wherein R1 is hydrogen, methyl, ethyl, tertiary butyl, tertiary butyl oxy carbonyl or benzyl, R2 is halogen, ester, carboxyl, cyano, amino or methoxy; benzylamine Ar is alkyl or alkoxy-substituted aromatic hydrocarbon, halogenated aromatics or heteroaromatic aromatics, iodisan is one of iodine, potassium iodide, sodium iodide,tetrabutyl ammonium iodide, sulfonium iodate salt, cesium iodide and N-Iodosuccinimide, oxidizing agent is one of hydrogen peroxide, peroxy tert butyl alcohol, potassium hydrogen persulfate, ditert butyl peroxide and chloramine salt, and solvent is one or two of ethyl acetate, acetonitrile, N, N-dimethylformamide, diethyl ether, dimethyl sulfoxide, 1,2-dichloroethane, methyl alcohol, ethyl alcohol, isopropanol, n-butyl ether, n-butyl alcohol, benzene, methylbenzene, 1,4-dioxane, methyl tert-butyl ether, dichloromethane, cyclohexane, petroleum ether, carbon tetrachloride, trichloromethane and tetrahydrofuran.