[Objective]To excavate and analyze the prescription and medication rules of Dr.XU Xiancha in treating children with external heat dampness.[Methods]Select Dr.XU Xiancha's medical records of pediatric external heat and dampness,and enter data according to items such as"name""gender""age""disease name""main symptom""tongue pulse""pathogenesis""treatment""drug composition"to establish a database of external heat and dampness medical records.By using application software such as Excel 2021,SPSS Modeler 18.0,Cytoscape,SPSS Statistics 25.0,and using frequency statistics,association rules and cluster analysis techniques,the frequency of drug use,drug meridians,four Qis and five flavors,and commonly used drug equivalence in the prescription were analyzed.A complex network analysis was conducted on all drugs to obtain the core prescription.[Results]A total of 995 prescriptions and 145 drugs were included.Among them,the top 10 high-frequency drugs ranked included Artemisiae Annuae Herba,Eupatorii Herba,Gardeniae Fructus Praeparatus,Trichosanthis Radix,Curcumae Radix,Crataegi Fructus,Galli Gigerii Endothelium Corneum,Liuyi Powder,Citri Reticulatae Pericarpium and Amomi Fructus Rotundus.The five flavors of high-frequency drug were mainly pungent,bitter and sweet,while the four Qis were mainly cold and warm.The meridians mainly belonged to the lung meridian,spleen meridian and stomach meridian.The top three in the combination of prescriptions were mainly Qi regulating drugs,heat clearing drugs and phlegm resolving drugs.Association rule analysis revealed 373 highly correlated drug pairs,including Artemisiae Annuae Herba-Eupatorii Herba,Artemisiae Annuae Herba-Gardeniae Fructus Praeparatus,and Eupatorii Herba-Gardeniae Fructus Praeparatus.Through cluster analysis,two types of drugs were obtained,among which type 1 had Artemisiae Annuae Herba,Eupatorii Herba,Gardeniae Fructus Praeparatus,Curcumae Radix,Galli Gigerii Endothelium Corneum,Trichosanthis Radix and Crataegi Fructus;Type 2 Citri Exocarpium Rubrum,Peucedani Radix.Type 1 was frequently used.The core prescription obtained from the complex network analysis results consisted of 10 drugs,including Artemisiae Annuae Herba,Eupatorii Herba,Gardeniae Fructus Praeparatus,Curcumae Radix,Galli Gigerii Endothelium Corneum,Trichosanthis Radix,Crataegi Fructus,Chrysanthemi Flos,Amomi Fructus Rotundus and Forsythiae Fructus.[Conclusion]Combined with the special physiological and pathological characteristics of children and the condition of dampness and heat in the Shao region,the clinical manifestation of summer-dampness in children is mainly caused by evil of lung,spleen and stomach.Dr.XU Xiancha's treatment of summer-damp external sensation is mainly based on the method of clearing heat and drying dampness and regulating Qi,supplemented by nourishing Yin and promoting fluid,strengthening the spleen and relieving food.