The invention provides a synthetic method of a pyridine [2,1-a] isoindole compound, which belongs to the technical field of organic synthesis. The method comprises the following steps: 1) phenylpyridine or a derivative a, bromoacetophenone or a derivative b, a cobalt/copper co-catalysis system and caesium salt are added in a reaction tube in order, and a solvent is added in the reaction tube; 2) the reaction tube is reacted under air condition at the temperature of 120-140 DEG C, wherein the reaction time is greater than or equal to 24 h; 3) a reaction mixture is filtered after the reaction iscompleted, the mixture is concentrated, the mixture is separated through column chromatography, and petroleum ether/ethyl acetate mixed liquor is washed to obtain the [2,1-a] isoindole compound c. The phenylpyridine or its derivative, bromoacetophenone or the derivative are taken as the reaction objects, the reaction is carried out under the cobalt-copper co-catalysis system, the reaction condition is mild, the reaction is easy to carry out, the cost of the catalysis system is low, the substrate universality is strong, and the yield is high.