To explore the medication characteristics of Chinese medicine for breast cancer to provide references for clinical application.Methods:Chinese medicinal prescriptions against tumors of breast cancer outpatients treated in Wuxi Traditional Chinese Medicine Hospital from January 1，2017，to December 31，2019，were collected.SQL was used for statistical analysis of data，and IBM SPSS Statistics 21 was used for factor analysis and cluster analysis.Results:A total of 2 569 Chinese medicinal prescriptions against breast cancer were collected，involving 398 Chinese herbal drugs，with a total frequency of 57 630.The top high-frequency Chinese herbal drugs included stir-fried Atractylodis Macrocephalae Rhizoma，Citri Reticulatae Pericarpium，Poria，and Pinelliae Rhizoma Praeparatum cum Zingibere et Alumine.The high-frequency drugs were mainly effective in tonifying deficiency，clearing heat，and resolving dampness.Cluster analysis revealed six drug combinations，and factor analysis suggested seven common factors.Conclusion:The formulation of Chinese medicinal prescriptions against breast cancer mainly follows the principles of tonifying deficiency to consolidate the root，soothing liver and regulating qi，and clearing heat，and pays attention to symptoms.