Objective :To investigate the effects of leptin on aortic valvular interstitial cells (VICs) transdifferentiation and reveal the role of leptin in the development of calcific aortic valve disease (CAVD). Method Porcine aortic VICs were separated and cultured via collagenase digestion. The VICs were incubated with leptin in different concentrations for 24 hours and the best stimulation concentration was determined by detecting ALP activity in the cell lysate. After incubated into optimal stimulation concentration for 24 hours, mRNA and protein expressions of α-SMA and OPN were detected by RT-PCR and Western blot， respectively. Results: Treatment with leptin enhanced the ALP expression of VICs and the optimal concentration was 100 ng/ml. Leptin treatment significantly promoted the mRNA and protein expression of OPN while α-SMA was not changed. Conclusion: Leptin can promote VICs calcification through inducing VICs transdifferent into osteoblast-like cells.