Abstract：Objective：To explore the medication rules of famous Chinese medicine physician KE Gan in the treatment of insomnia，and to provide reference for clinical practice. Methods：The medical records of patients with insomnia in the outpatient department of famous Chinese medicine physician KE Gan were collected， and 205 prescriptions were included in the database according to the inclusion and exclusion criteria. The Traditional Chinese Medicine Inheritance Calculate System (TCMICS) V3.0 was used to analyze the data of all prescriptions，and the medication rules and academic thoughts were summarized by using kmeans and cluster statistics. Results： A total of 125 kinds of Chinese medicinals were involved of the prescriptions， among which the frequency of use was relatively high， such as Ziziphi Spinosae Semen， Platycladi Semen，Albiziae Cortex，Rehmanniae Radix，Lilii Bulbus，Polygalae Radix and Poria cum Radix Pini. Through the analysis of the four properties and five flavors and the effect of meridian tropism， the main drugs were mild in nature， sweet in flavor， enter the heart and liver meridians， with functions of calming the mind，supplementing deficiency and clearing heat. According to the association rules，7 core drugs were obtained： Ziziphi Spinosae Semen， Platycladi Semen， Albiziae Cortex， Rehmanniae Radix， Lilii Bulbus， Polygalae Radix and Poria cum Radix Pini. The combination of "Ziziphi Spinosae Semen and Platycladi Semen" has the highest frequency. Through cluster analysis， the empirical formula was obtained：Ziziphi Spinosae Semen，Platycladi Semen，Albiziae Cortex，Rehmanniae Radix，Lilii Bulbus， Polygalae Radix，Poria cum Radix Pini and Angelicae Sinensis Radix. Conclusion：The principle of famous Chinese medicine physician KE Gan treating insomnia is to supplement deficiency and drain excess，adjust yin and yang，and first emphasize the method of calming the mind and supplementing deficiency，among which，pay attention to the application of nourishing the heart and liver，enriching yin and blood，soothing the liver，and at the same time use the method of "clearing heat，removing dampness，dissolving blood stasis，calming the liver and regulating qi".