Disclosed is a preparation method for an isoxazole compound and an intermediate thereof, the method comprising: a compound (I), as the starting material, is subjected to a substitution reaction with a compound (II) in the presence of a base, and subsequently to an oxidation reaction to prepare an intermediate acid (III); the intermediate acid (III) is methyl esterified to obtain an intermediate (IV); the intermediate (IV) is subjected to thionation to obtain an intermediate (VI); the intermediate (VI) is condensed with cyclopropyl methanone under a basic condition to obtain an intermediate (VIII); the intermediate (VIII) is subjected to alkene etherification reaction with ortho-formate and cyclized with hydroxylamine hydrochloride to obtain an intermediate (X); the methylthio of the intermediate (X) is oxidized by hydrogen peroxide to obtain isoxazole compound (XI). The starting material used in the present preparation method is readily available, and the preparation method has high productivity and purity, produces less industrial waste water, gas and residue, and has low cost and good industrial value.