Abstract: A novel method for synthesizing carfentanil is researched in this work. N-Boc-protected piperidinone was used as the starting material. The carfentanil was achieved via synthetic rout involving five steps: Bargellini reaction, N-acylation, methylation, deprotection and N-alkylation. The overall yield of target compound was 31.6％. The structures of intermediates and final product were determined by infrared spectroscopy, nuclear magnetic resonance spectroscopy and mass spectrograph.