The invention discloses a preparation method of 5-(4-cyanophenoxy)-2, 3-dihydro-1-hydroxy-2, 1-benzoxaborole intermediate. The 5-(4-cyanophenoxy)-2, 3-dihydro-1-hydroxy-2, 1-benzoxaborole intermediatecomprises a structure as shown in a formula IV. The preparation method comprises the following steps: ensuring that a compound as shown in a formula I and 4-fluorobenzonitrile perform contact reaction under the existence of a first organic solvent and first alkali, so as to obtain a compound as shown in a formula II; ensuing that a compound as shown in the formula II and a bromination reagent perform contact reaction under the existence of a second organic solvent and a catalyst, so as to obtain a compound as shown in a formula III; ensuing that a compound as shown in the formula III and alkali metal boron hydrate perform contact reaction under the existence of a third solvent, so as to obtain a compound as shown in the formula IV. The preparation method uses the reaction material 4-fluorobenzonitrile as ortho-position steric perssad, cancels the use of a protecting group, improves the bromination reaction selectivity, is low in process cost and cheap in material prices, and can be better applied to industrial production.