The invention discloses a [1,2,4]-triazol [4,3-a] pyridines compound and a synthesis method thereof. The compound has a structure general formula shown as the formula (I), wherein R1 is selected fromaryl and heterocyclic groups; R2 is selected from hydrogen, alkyl, alkoxy, halogen or aryl. According to the synthesis method, alpha-ketonic acid and 2-hydrazinopyridine are used as raw materials; KIis used as a catalyst; Na2CO3 is used as alkali; TBHP is used as an oxidizing agent; 1,4-dioxane is used as a solvent; after a series of serial connection cyclization and decarboxylation aromatization, the [1,2,4]-triazol [4,3-a] pyridines compound is obtained. The [1,2,4]-triazol [4,3-a] pyridines compound is prepared under the condition of no transition metal and has the advantages that the reaction is efficient and fast; the conditions are mild; the substrate is simple and can be easily obtained; the applicability is wide; the reaction time is short; the yield is high, and the like; meanwhile, the post treatment of the reaction is simple and convenient; the harm to experiment operators is reduced; the environment-friendly effect is achieved; the green chemical requirements are met.