The invention discloses a synthetic method of perylene red 620 as perylene red dye. The method is characterized by comprising the following steps: 1,6,7,12-tetrachloro-3,4,9,10-perylenetetracarboxylicdianhydride is taken as a raw material and subjected to a reaction with 2,6-diisopropylanilineby catalysis of a catalyst under protection of inert gas, and the intermediate N,N'-bis(2,6-diisopropyl)phenyl-1,6,7,12-tetrachloro-3,4,9,10-perylenetetracarboxylic diimide is obtained; the intermediate is subjected to a reaction with phenol, and a crude perylene red 620 product is obtained; the crude product is washed and subjected to other processing, and perylene red 620 with higher purity is obtained. After introduction of the catalyst, synthetic reaction temperature of the intermediate is reduced, and reaction time is shortened by 2 / 3; the original column chromatographic process is replaced with a cooling, standing and suction filtration method, and accordingly, purity of the intermediate isimproved; the method has the characteristics of safe and reasonable process, simple processing steps, high yield, low cost, high product purity and the like.