An application of tetrahydrobenzazole in the preparation of an agricultural fungicide or a fungicide composition and a preparation method therefor. A 4-((-(2-chloro-4-(4-chlorophenoxy)phenyl)-4-methyl-1,3-dioxapentan-2-yl)methyl)-4H-1,2,4-triazole(tetrahydrobenzazole) compound has application in agricultural fungicides, having the structural formula shown in formula I is provided. Also, the embodiments transform waste that can usually only be treated as a hazardous organic waste solid, accounting for 35-40% of the production process of an agricultural fungicide difenoconazole, into a useful pesticide, significantly reducing discharge of hazardous organic waste solids, and alleviating environmental protection pressure on manufacturers. The preparation method of the embodiments can also increase the yield of difenoconazole and reduce costs.
