To investigate the clinical effect of Nuangong Baoyu Pill combined with metformin on polycystic ovary syndrome (PCOS). Methods:A total of 86 PCOS patients in Hainan Modern Women and Children's Hospital were selected as the research objects and were randomly divided into a control group and an observation group, with 43 cases in each group. The control group was treated with metformin, and the observation group was treated with Nuangong Baoyu Pill combined with metformin. The application effect of the 2 groups was compared. Results:After treatment, the ovarian volume (8.13±1.75) cm3 and endometrial thickness (0.93±0.28) cm in the observation group were lower than those in the control group (9.36±1.95) cm3 and (1.14±0.36) cm (P<0.05); after treatment, follicle stimulating hormone (FSH) (4.84±0.69) U/L, luteinizing growth hormone (LH) (8.94±2.63) IU/L, estradiol (E2) (70.93±3.16) pg/mL in the observation group were lower than those in the control group (5.21±0.78) U/L, (11.06±3.28）IU/L、（73.02±3.35）pg/mL(P<0.05). The total effective rate of the observation group (90.70%) was higher than that of the control group (72.09%) (P<0.05); the incidence of adverse reactions in the observation group (13.95%) was not significantly different than that in the control group (9.30%) (P>0.05); the ovulation rate (88.37%), pregnancy rate (83.72%) in the observation group were higher than those in the control group (69.77%) and (62.79%), and the early pregnancy abortion rate (6.98) was lower than that in the control group (25.58%) (P<0.05). Conclusion:Nuangong Baoyu Pill combined with metformin can effectively reduce endometrial thickness and ovarian volume, regulate serum hormone levels, promote ovulation, reduce the risk of abortion, improve the efficacy, with good safety.