The invention discloses a trifloxystrobin synthesizing method, and relates to the preparation of trifloxystrobin in organic chemicals. The trifloxystrobin synthesizing method comprises the following steps of using hydroxy methyl phenylacetic acid lactone as raw material to react with TBN (tributyrin), absolute methanol and sodium methoxide to obtain (E)-3-keto-4-(isonitroso)isochroman; using the (E)-3-keto-4-(isonitroso)isochroman to react with acetone and potassium carbonate, and dropwise adding the acetone solution of dimethyl sulfate after a large amount of bright yellow solids occurs, so as to obtain (E)-3-keto-4-(methoxyimino)isochroman; dissolving the obtained (E)-3-ketone-4-(methoxyimino)isochroman by methanol, and dropwise adding thionyl chloride under the low-temperature condition to prepare (E)-2-chlororated methyl-alpha-methoxyimino methyl phenylacetate; after the catalysis of 3-(trifluoromethyl)acetophenone and hydroxylamine hydrochloride, using absolute ethyl alcohol and as solvent to obtain light earthy yellow solid (E)-3-(trifluoromethyl)acetophenone oxime; enabling the (E)-2-bromomethyl-alpha-methoxyimino methyl phenylacetate and the (E)- 3-(trifluoromethyl)acetophenone oxime to react in a DMF (dimethyl formamide) solution of the potassium hydroxide, so as to obtain the white solid of trifloxystrobin.