The invention relates to a synthesis method of chiral fenoxanil. The synthesis method of the chiral fenoxanil is characterized in that chiral ethyl lactate is subjected to sulfonylation reaction to obtain sulfonic acid ester; the sulfonic acid ester reacts with 2,4-dichlorophenol to generate 2-(2,4-dichlorophenoxy) ethyl propionate; the 2-(2,4-dichlorophenoxy) ethyl propionate and 2,-amino-2,3-dimethyl nitrile are subjected to ammonia ester exchange reaction to generate corresponding chiral fenoxanil, wherein the molar ratio of the 2-(2,4-dichlorophenoxy) ethyl propionate to the 2,-amino-2,3-dimethyl nitrile is 1:1 and the reaction temperature is 60 to 85 DEG C. The method is simple in synthesis route, hydrolysis and chlorination are not needed, little waste water and waste gas are generated, a high environmentally-friendly benefit is achieved, the production cost is greatly reduced, the condition is mild, the fenoxanil with optical chirality can be synthesized in an oriented mode by selecting different configuration of ethyl lactate, and important significance of further exploring the optical property of the fenoxanil is achieved.