Abstract: Objective To investigate the prescription regularity in treating HSP.Methods The electronic medical records of 107 HSP child patients in the Affiliated Hospital of Shandong University of Traditional Chinese Medicine from May 2016 to September 2020 were collected, and were screened and analyzed which were used to build a prescription database. Frequency statistics method, association rules and cluster analysis(K-means algorithm+regression models) were used to process data mining. Analyze the prescription regularity of traditional Chinese medicine in treating HSP with the help of TCMISS(V3.0) The property and flavor, frequency, meridian distribution, effect and core drug combination of the core drugs were studied.Results There were 16 Chinese herbs with frequency of usage≥20, and the herbs with high frequency of usage included: honey-fried licorice root, rhizoma atractylodis, moutan bark, semen coicis, golden cypress, lithospermum, etc. There were 23 herb pairs with frequency of usage≥30，and the herb pairs with high frequency of usage included rhizoma atractylodis-golden cypress,rhizoma atractylodis-moutan bark-semen coicis, moutan bark-radix paeoniae rubra, etc. Main taste was bitter and sweet, main drug property was cold, and the main meridian distribution was in lung, spleen, liver and heart. Conclusion The treatment methods for HSP in our hospital were summarized, such as "bitter and sweet law" and "dispelling latent evil". The main drugs are to clear away heat and toxic materials and promote blood circulation and remove blood stasis, and tonifying drugs are used at the same time.

Key words: HSP, Latent evil, Blood stasis, Defensive qi；TCMISS