A 3-cyanoindole compound synthesis method includes: firstly, taking indole compound, benzyl cyanide and CuI according to the molar ratio of 1:1-2:1-2, placing the indole compound, the benzyl cyanide and the CuI in a reaction vessel, and adding solvent into the reaction vessel until the indole compound and the benzyl cyanide are completely dissolved; then, placing the reaction vessel in oil bath at the temperature of 100-130 DEG C with stirring for reaction for 30-34h, cooling to the room temperature, adding water as same as the solvent in volume, and extracting for 2-4 times by the aid of dichloromethane; and finally, separating using silica gel column chromatography prior to reduced pressure distillation so that the product, namely, the 3-cyanoindole compound is obtained.
