Abstract：Objective：To analyze the medication rules of Professor LI Liang in treating chronic insomnia based on data mining. Methods： The outpatient medical records of Professor LI Liang in treating chronic insomnia were collected. Excel 2016 was used to establish a database and analyze the frequency， nature and flavor and meridian entries of Chinese medicinals in the prescriptions. SPSS Modeler 18.0 was used to analyze the core medicinals. IBM SPSS Statistics 26.0 was used for factor analysis and clustering analysis of the core medicinals. Results： A total of 265 medical cases were included， with 308 prescriptions， involving 169 Chinese medicinals. The top five Chinese medicinals in the use frequency were Margaritifera Concha，Bupleuri Radix，Fried Ziziphi Spinosae Semen，Ostreae Concha and Pinelliae Rhizoma and the top three in nature were cold，neutral and warm；the top three in flavor were sweet， bitter and pungent； the top five meridian entries were the liver， heart， lung， spleen and gallbladder. The association rule analysis showed that the core medicinal combinations for insomnia were Ostreae Concha-Os Draconis， Bupleuri Radix-Arisaema cum Bile，Bupleuri Radix-Citri Reticulatae Pericarpium Viride，etc. A total of nine common factors were extracted by factor analysis， and three prescriptions were obtained by systematic clustering analysis. Conclusion：Professor LI Liang treats chronic insomnia by using Chinese medicinals for soothing the liver，clearing heat and resolving phlegm， calming mind by heavy settling， enriching yin and invigorating blood， and transporting nutrients in the spleen and stomach. It is to modify the basic prescriptions of Chaiqin Wendan Decoction，Suanzaoren Decoction，Jiaotai Pills，Liuwei Dihuang Pills and Anshen Dingzhi Pills.