The present invention relates to the application of using leptin to cure liver cancer, which provides the patient having liver cancer with an effective dose of therapeutic medicine, a therapeutic procedure or a screening platform. This invention is characterized by applying leptin combined with medroxyprogesterone acetate(MPA) to a patient for contacting with liver cancer cells, wherein leptin can be obtained by adding leptin form outside of the patient or by increasing the physiological concentration of leptin inside the patient. The leptin enhances and accelerates the MPA to poison liver cancer cells through an interaction of a leptin receptor and a progesterone receptor. By MPA+leptin having pharmacologic specificity on the epithelial cell line of normal liver and the cell line of liver cancer and no unwanted side effects, MPA+leptin can improve the overall survival rate of patient with liver cancer. Wherein, the expression of leptin can further be a predictive factor of treatment effect on curing the patient with MPA, and a prognostic factor of survival time.