The paper introduces the research significance of deuterated drugs and discusses the synthesis of deuterated compounds by modern organic synthesis methods.This article described a selects deuterated synthesis of traditional anti-allergic drug cyproheptadines.The bis(norbornadiene)rhodium(I) tetrafluoroborate was used as catalyst, deuterated methanol as deuterium source, and the reaction was refluxed for 48 h.The reaction can smoothly undergo hydrogen-deuterium exchange to give the deuterated cyproheptadine products in 87 % yields with 98 % deuteration rate.The synthesized product was characterized by GC-MS spectrometry, 1 H-NMR, 13 C-NMR and 2 H-NMR to confirm the structure of the target product.