4-Formylaminoantipyrine was synthesized by acylation of 4-aminoantipyrine and methyl formate. The results showed that the molar ratio of 4-aminoantipyrine to methyl formate was 1∶2.0, the reaction temperature was 40 ℃, the reaction time was 5 h, the yield of 4-formylaminoantipyrine was 96%. The purity of the target compound was 98.7% by liquid chromatography. This process has mild reaction conditions, low cost, small environmental pollution, high purity and easy quality control.