The present invention provides a 2-fluoro-6-trifluoromethylbenzenesulfonyl chloride synthesis method. According to the reaction formula defined in the specification, o-trifluoromethylaniline is used as a raw material, and acylation, alkylation, nitration, dealkylation, reduction, diazotization fluorination, hydrolysis and sulfonylation are performed to synthesize an intermediate 2-fluoro-6-trifluoromethylbenzenesulfonyl chloride. According to the present invention, the target is that the synthesis process is suitable for the industrial production, the starting raw material is easy to obtain, the raw material cost is low, the process operating condition is mild, and the method is suitable for industrial production.