Abstract：Objective：To analyze the clinical medication rules of Professor QU Fan in treating polycystic ovary syndrome （PCOS） based on data mining technology. Methods：Traditional Chinese medicine medical records of PCOS patients treated by Professor QU Fan at the Women's Hospital， School of Medicine of Zhejiang University from January 2021 to April 2024 were collected. Prescriptions meeting inclusion criteria were recorded，organized，and uploaded to the Traditional Chinese Medicine Inheritance Computing System （V3.0） for frequency statistics analysis， association rules analysis， and cluster analysis. Results： A total of 712 valid prescriptions involving 92 Chinese medicinal herbs were analyzed. The top five most frequently used herbs were Pseudostellariae Radix， Glycyrrhizae Radix et Rhizoma Praeparata cum Melle， Polygonati Rhizoma， Rubi Fructus， and Epimedii Folium. Herbs were predominantly warm or neutral in the four properties，and sweet，bitter，or pungent in the five flavors. Cluster analysis identified four frequently-used associated prescriptions. Conclusion：Professor QU Fan's treatment for PCOS focuses on tonifying the kidney and strengthening the spleen as the fundamental principle，primarily using herbs with sweet in flavors and warm in properties，supplemented appropriately with herbs of bitter in flavors and cold in properties for balance. In terms of the therapeutic effects，the herbs usually involves tonifying deficiency and followed by promoting blood circulation to resolve stasis，while herbs for clearing heat，draining dampness，regulating qi，and harmonizing the stomach were selected depending on individual conditions，thus for activating blood and removing stasis，clearing heat and eliminating dampness，and tranquilizing mind and improving sleep.