The disclosure provides a synthesis method of 2,4,6-trifluorobenzylamine, belonging to the technical field of chemical synthesis. The synthesis method is characterized by comprising the following steps: (1) allowing pentachlorobenzonitrile as a raw material to undergo fluoridation reaction with a fluoridation agent based on 2,4,6-trifluoro-3,5-dichlorobenzonitrile as a solvent to obtain 2,4,6-trifluoro-3,5-dichlorobenzonitrile; (2) hydrogenating the obtained 2,4,6-trifluoro-3,5-dichlorobenzonitrile with hydrogen in the presence of organic carboxylic acid, based, on palladium carbon as a catalyst to obtain 2,4,6-trifluoro-3,5-dichlorobenzylamine; and (3) hydrogenating the obtained 2,4,6-trifluoro-3,5-dichlorobenzylamine with hydrogen in a solvent in the presence of a catalyst to obtain 2,4,6-trifluorobenzylamine. The synthesis method has the advantages of low raw material cost, short reaction steps, high reaction yield, good product purity simple operation and the like, and is suitable for industrial production.