Objective,2,To analyze the prescription and medication patterns of Professor Sun Shidao in treating skin diseases and summarize his academic thoughts.,Methods,2,The cases of skin diseases treated by Professor Sun Shidao were collected and a medical record database was established. The statistical software SPSS 22.0 was used for frequency analysis， and Apriori algorithm of IBM SPSS Modeler 18.0 was used for association rules and network analysis to mine the prescription and medication patterns.,Results,2,①A total of 7，289 patients involving 5，239 prescriptions and 402 traditional Chinese herbal medicines （TCHMs） were included. There were 346 disease names in modern medicine and 223 disease names in traditional Chinese medicine （TCM） ［The number of patients suffering from dermatitis eczema （damp sore） was the highest， followed by the number of patients with lupus erythematosus （red butterfly sore）， acne （comedo）， and psoriasis （white tinea）］. ②The drugs commonly used by Prof. Sun Shidao for treating skin diseases included Mudanpi （Moutan Cortex）， Danshen （Salviae Miltiorrhizae Radix et Rhizoma）， Dihuang （Rehmanniae Radix）， Xuanshen （Scrophulariae Radix）， Zhimu （Anemarrhenae Rhizoma）， Huangqin （Scutellariae Radix）， Tufulin （Smilacis Glabrae Rhizoma） and Baihuasheshecao （Hedyotis Diffusae Herba）. By analyzing the classification of diseases and TCM syndromes， it was found that Professor Sun had adopted different methods for different diseases and syndromes. When treating acne， he used the method of clearing heat and dampness as the main method， taking into account nourishing yin and reducing fire； When treating lupus erythematosus， he used the methods of nourishing yin and benefiting qi， cooling blood and nourishing blood； When treating psoriasis， he focused on the treatment of blood， putting equal emphasis on the methods of cooling blood， nourishing yin and invigorating blood. ③According to the results of association rule analysis， Professor Sun commonly used 20 TCHMs for the treatment of skin diseases， including Baihuashesehcao （Hedyotis Diffusae Herba）， Difuzi （Kochiae Fructus）， Kushen （Sophorae Flavescentis Radix）， Shanyao （Dioscoreae Rhizoma）， Baizhu （Atractylodis Macrocephalae Rhizoma）， Xuanshen （Scrophulariae Radix）， Yuzhu （Polygonati Odorati Rhizoma）， Baixianpi （Dictamni Cortex）， Dihuang （Rehmanniae Radix） and Tufulin （Smilacis Glabrae Rhizoma）. Among them， Dihuang （Rehmanniae Radix）， Tufulin （Smilacis Glabrae Rhizoma）， Baixianpi （Dictamni Cortex）， Yuzhu （Polygonati Odorati Rhizoma） and Mudanpi （Moutan Cortex） showed the closest network relationship with other TCHMs. According to the network analysis， there were 6 medicinal groups containing 7 TCHMs， among which Baixianpi （Dictamni Cortex）， Pugongying （Taraxaci Herba） and Baihuasheshecao （Hedyotis Diffusae Herba） were strongly correlated.,Conclusions,2,Professor Sun Shidao specializes in the treatment of dermatitis eczema （damp sore）， lupus erythematosus （red butterfly sore）， acne （comedo） and psoriasis （white tinea）. He often uses the method of clearing heat as the basis， and combines it with other methods such as wind-dispelling method， dampness-relieving method， blood-cooling method and yin-nourishing， etc. He is good at using the medication group of Baixianpi （Dictamni Cortex）， Pugongying （Taraxaci Herba） and Baihuasheshecao （Hedyotis Diffusae Herba）， etc.