The invention discloses a synthesis method of 2, 6-dichloroaniline. The method uses aniline as a raw material, and comprises the following steps: 1) adding aniline into dilute hydrochloric acid, then dropwise adding hydrogen peroxide for a chlorination reaction, and adding water into the obtained 2, 4, 6- trichloroaniline hydrochloride to carry out steam distillation, so as to obtain 2, 4, 6-trichloroaniline; 2) reacting 2, 4, 6-trichloroaniline with acetic anhydride to obtain 2, 4, 6-trichloroacetanilide; 3) adding the obtained 2, 4, 6-trichloroacetanilide into an autoclave, then adding a solvent and a catalyst, and filling in hydrogen for a reduction reaction, so as to obtain 2, 6-dichloroacetanilide; and 4) adding 2, 6-dichloroacetanilide into an alkali solution and heating for reaction, so as to finally obtain 2, 6-dichloroaniline. The synthetic method of 2, 6-dichloroaniline has the advantages of low cost, high conversion rate and simple post-treatment, and is suitable for industrial production.