The invention discloses a benzodihydropyrone derivative and a preparation method thereof. The method includes: adopting a phenoxy-containing alkynone compound as the reaction raw material, taking goldtrichloride as the catalyst, using chlorobenzene as the solvent, and employing 2, 6-dichloropyridine nitrogen oxide as the oxidant, carrying out reaction at 55DEG C-65DEG C for 2h-3h to obtain the benzodihydropyrone derivative. Specifically, the alkynone compound has a chemical structural formula shown as A, and the benzodihydropyrone derivative has a chemical structural formula shown as B; R1 isselected from C1-C12 alkyl, substituted aryl, aromatic heterocycle or thick ring; R2 is selected from hydrogen atom, C1 C12 alkyl, various substituent aryl, aromatic heterocyclic or condensed ring;R2 is selected from hydrogen atom, C1-C12 alkyl, various substituted aryls, aromatic heterocycles or thick rings; the formula A is shown as the specification; and the formula B is shown as the specification. According to the method provided by the invention, the product has the advantages of easy separation, high yield, good substrate adaptability, simple reaction process and great application potential.