The invention discloses a method for synthesizing formamide derivatives by molybdenum catalyzed formylation reaction. The method includes that the formamide derivatives are generated by one-pot reaction of amine compounds and formamide compounds under the catalytic action of molybdenum salts and/or molybdenum oxides. Reaction methods and catalysts are cheap and easy to acquire, reaction steps andoperations are simple, the method has advantages of high reaction selectivity, high yield, expandability in reaction and the like, and defects of high toxicity of reaction agents, expensive catalysts,complex reaction steps, high quality of by-products and the like in the prior art are overcome.