Objective:To observe the effect of Cangfu Daotan decoction on follicular development in patients with phlegm-dampness type polycystic ovary syndrome (PCOS), hoping to provide reference for the treatment of PCOS patients with phlegm dampness. Methods: A total of 80 PCOS patients with phlegm dampness admitted in the Third People's Hospital Affiliated to Fujian University of Traditional Chinese Medicine from January 2021 to December 2021 were selected and randomly divided into the control group (n=40) and the experimental group (n=40). The experimental group was treated with Cangfu Daotan decoction for 6 months, while the control group was given the placebo. The phlegm-dampness syndrome score, ovulation rate, adipose factor (Apelin), and insulin resistance index (HOMA-IR) of the two groups of patients were observed before and after treatment, and the correlation between Apelin and HOMA-IR was analyzed. Results: There was no statistically significant difference in the average age, infertility years, body mass index, etc. of the two groups (P＞0.05). No statistically significant difference in the score of phlegm-dampness syndrome, ovulation rate, Apelin, and HOMA-IR levels was found in the control group before and after treatment (P＞0.05). After treatment, the score of phlegm-dampness syndrome in the experimental group decreased (P＜0.05), the ovulation rate increased (P＜0.05), and the levels of Apelin and HOMA-IR decreased (P＜0.05). Pearson correlation analysis results showed a positive correlation (P＜0.05) between Apelin levels and HOMA-IR levels after treatment. Conclusion: Cangfu Daotan decocotion can effectively improve phlegm dampness symptoms and insulin resistance in patients with phlegm-dampness type PCOS, reduce serum Apelin levels, promote follicular development, and increase ovulation rate.