Abstract： Objective： To observe the clinical effect of Fangfeng Tongsheng Powder combined with Metformin for obese polycystic ovary syndrome (PCOS). Methods： A total of 140 cases of patients with obese PCOS were divided into the control group and the observation group according to the random number table method， with 70 cases in each group. The control group was treated with Metformin， and the observation group was treated with Fangfeng Tongsheng Powder combined with Metformin. Before and after treatment，the severity scores of acne，traditional Chinese medicine (TCM) syndrome scores，body mass index (BMI)，ovarian volume，glucose metabolism，lipid metabolism and sex hormone indexes were compared between the two groups. Basal body temperature (BBT) in the two groups was compared after 1 month and 3 months of treatment. The clinical effects and the incidence of adverse reactions were compared between the two groups. Results：During the study period，3 cases were removed and 4 cases dropped out in the control group； 3 cases were removed and 4 cases dropped out in the observation group； a total of 63 cases were completed in each group. The total effective rate was 92.06% in the observation group，higher than that of 79.37% in the control group (P＜0.05). The severity scores of acne， TCM syndrome scores， BMI， and ovarian volume in the the two groups were lower than those before treatment (P＜0.05)，and the above indexes in the observation group were lower than those in the control group (P＜0.05). After treatment，the levels of follicle stimulating hormone (FSH)，anti-mullerian hormone (AMH)， estradiol (E2)， luteinizing hormone (LH)， progesterone (P)， low- density lipoprotein cholesterol (LDL-C)，total cholesterol (TC)，triglyceride (TG)，fasting blood glucose (FBG)，and fasting insulin (FINS)， and Homeostatic Model Assessment of Insulin Resistance (HOMA- IR) in the two groups were decreased when compared with those before treatment (P＜0.05)， and the levels of high- density lipoprotein cholesterol (HDL- C) were increased (P＜0.05). After treatment， the levels of sex hormone， glucose metabolism indexes，LDL-C，TC，and TG in the observation group were lower than those in the control group (P ＜ 0.05) ， and the level of HDL-C was higher than that in the control group (P ＜ 0.05). After 3 months of treatment，the proportion of single-phase BBT in the two groups was lower than that after 1 months of treatment (P＜0.05)，and the proportions of occasional dual-phase BBT and dual-phase BBT were higher than those after 1 months of treatment (P＜0.05)； the proportion of single- phase BBT and occasional dual- phase BBT in the observation group was lower than that in the control group (P＜0.05)， and the proportions of dual-phase BBT were higher than those in the control group (P＜0.05). There was no significant difference being found in the comparison of the incidence of adverse reactions between the two groups (P＞0.05). Conclusion： Fangfeng Tongsheng Powder combined with Metformin has a definite curative effect in treating obese PCOS，which can reduce the body mass of patients，improve the function of glucose and lipid metabolism and regulate the levels of sex hormones，with high safety.