Abstract: Objective To study the change of serum leptin expression level in patients with liver cancer and its clinical significance. Methods A total of 290 patients were enrolled in this study. The patients were divided into liver cancer group（n=104）, operation group（n=86）, and normal control group（n=100）. Total cholesterol（TC）, triglyceride（TG）, alkaline phosphotase（ALP）and total bilirubin（STB）were detected with an automous biochemical analyzer, while leptin and α-fetal proteins （AFP） were detected by radioimmunoassay. Results The serum TG, TC, ALP, STB, leptin, AFP levels in liver cancer group and the serum TG, leptin and AFP levels in operation group were significantly higher than those in normal control group（P＜0.05）. Leptin and AFP levels in operation group were obviously lower than liver cancer group（P＜0.05）. Serum leptin,TC was significantly related with TG. No significant change was observed in leptin and AFP, ALP, and STB levels. Conclusion Leptin participates in the pathogenesis and development of liver cancer by promoting angiogenesis in cancer tissues.