To observe the effects of Jiangtang Xiaozhi Pills (JTXZP) on Lee's index, blood lipid and pathological morphology of obesity rat models and to study its pharmacology. Methods:SD rats were fed for 18 weeks with high-fat diet to induce rat model. The animals were divided into 7 groups of normal control group (common diet), model group, metformin group (0.3 g/kg), simvastatin group (4 mg/kg) and high-dose, middle-dose and low-dose JTXZP groups (2 g, 4 g and 8 g crude drug/kg), respectively, with 12 rats in each group. The duration of treatment was 8 weeks, 1 time /day. The changes in body weight (BW) and dietary intake were observed during the treatment time, and Lee's index, blood lipid and free fat acid (FFA) were tested. The morphological observation was conducted on the liver and the fat. Results: Compared with the model group after 8 weeks of drug administration, the symptoms of obesity were significantly improved, the body weight (P<0.05~0.01), Lee's index (P<0.05~0.01), total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C) were all decreased significantly (P<0.05). High density lipoprotein cholesterol (HDL-C) in high-dose group increased significantly (P<0.01), and TC/HDL-C decreased (P<0.05). Low-dose group LDL cholesterol (VLDL-C) decreased (P< 0.05). FFA values were decreased in all three dose of JTXZP groups (P<0.01). Pathology results showed that there was improvement of different levels in the liver and fat at all dose of groups of JTXZP. Each dosage group of JTXZP had a significant improvement in hepatic steatosis (P<0.05). Conclusion: JTXZP could decrease the body weight, blood fat and improve the hepatic steatosis. Its mechanism may be related to reducing FFA and improving lipid metabolic disorder．