Abstract： Objective： To observe the therapeutic effects of Zishen Jianpi Tiaochong Decoction combined with Letrozole in the treatment of polycystic ovary syndrome （PCOS）. Methods：A total of 120 patients with PCOS treated at Wenzhou People's Hospital from May 2022 to May 2023 were selected. All patients had undergone Drospirenone- Ethinylestradiol pretreatment to normalize their sex hormone levels. They were divided into three groups （40 cases each） using a numerical lottery method： the Chinese medicine group， the western medicine group， and the combination group. The Chinese medicine group was treated with Zishen Jianpi Tiaochong Decoction， the western medicine group with Letrozole，and the combination group with both Zishen Jianpi Tiaochong Decoction and Letrozole. The changes in the longest diameter of dominant follicles，ovarian volume，and endometrial thickness were compared before and after treatment among the three groups. Additionally， ovulation rates， pregnancy rates， and the incidence of adverse reactions were compared. Results： After treatment， the longest diameter of dominant follicles and endometrial thickness were increased significantly in all three groups （P＜0.05）， while ovarian volume were decreased significantly （P＜0.05）. The combination group showed a greater increase in the longest diameter of dominant follicles and endometrial thickness compared to the Chinese medicine and western medicine groups （P＜0.05），and a smaller ovarian volume （P＜0.05）. The ovulation rate in the combination group was 85.00% （34/40），higher than that in the Chinese medicine group （57.50%， 23/40） and the western medicine group （65.00%， 26/40） （P＜0.05）. The pregnancy rate in the combination group was 45.00% （18/40）， higher than that in the Chinese medicine group （17.50%， 7/40） and the western medicine group （22.50%， 9/40） （P＜0.05）. The incidence of adverse reactions was 25.00%（ 10/40） in the western medicine group，higher than that in the Chinese medicine group（ 5.00%， 2/40） and the combination group （12.50%， 5/40） （P＜0.05）. Conclusion： For patients with polycystic ovary syndrome who have undergone Drospirenone-Ethinylestradiol pretreatment，the combination of Zishen Jianpi Tiaochong Decoction and Letrozole can improve ovarian morphology， increase endometrial thickness， promote ovulation， and enhance the probability of successful pregnancy，with high safety.