Abstract： Objective： To analyze the medication rules of Professor ZHANG Ying， a renowned traditional Chinese medicine （TCM） expert in Yunnan Province， in the treatment of psoriasis vulgaris based on data mining. Methods： Case data of psoriasis vulgaris treated by Professor ZHANG Ying were collected. The Traditional Chinese Medicine Inheritance Support system V2.5 was used to establish a database. Statistical functions of the software were applied to analyze the frequency， four properties， five flavors， and channel entries of the herbs. Data mining for prescription rules and new prescription analysis through association rule analysis and cluster analysis was performed，and the results were presented in charts and network visualizations. Results： A total of 261 prescriptions for the clinical treatment of psoriasis vulgaris were screened，involving 126 herbs. Ten herbs were used with a frequency over 100 times： Armeniacae Semen Amarum， Glycyrrhizae Radix et Rhizoma， Zingiberis Rhizoma， Atractylodis Macrocephalae Rhizoma，Galli Gigerii Endothelium Corneum，Crataegi Fructus，Poria，Platycodonis Radix，Astragali Radix，and Clematidis Radix et Rhizoma. In terms of the four properties，the herbs were mainly warm. In terms of the five flavors， they were mainly acrid and sweet. In terms of channel entries， they were mainly the spleen， lung， and stomach channels. Based on association rule analysis，22 core herbal combinations with a usage frequency ≥100 were identified for the treatment of psoriasis vulgaris. Through entropy-based clustering analysis of complex systems， three potential new prescriptions were excavated. Conclusion： In clinical treatment of psoriasis vulgaris， Professor ZHANG Ying does not rigidly adhere to conventional syndrome types. By integrating the clinical characteristics of the disease， she focuses on supporting yang as the foundation， avoids misuse of warm-supplementing herbs， combines invigorating blood and nourishing yin，and applies syndrome differentiation-based treatment.