To discuss medicine law of Professor Change Ke when treating the disease of Henoch-Schonlein Purpura Nephritis.Methods:Cases from Affiliated Hospital of Chengdu University of Traditional Chinese Medicine were selected from January 2016 to January 2017.Frequencies analysis，cluster analysis and association rules were used to find out some medicine law from clinical prescriptions of Professor Ke Change.Results:A total of 46 kinds of herbs were used with frequency which is higher than 10%.Among all them，the heat-clearing medicinal and the tonifying and replenishing medicinal were most frequently used.The analysis also showed that the herbs with clod and warm properties were most frequently used.Herbs with bitter taste and sweet taste were most frequently used.Researcher got 4 clusters via Frequencies analysis and 442 rules acquried based on association rules.Conclusion:According to all above analyses，Professor Chang Ke considered toxic heat，deficiency，blood stasis，dampness and wind as important pathological factors of Henoch-Schonlein Purpura Nephritis.Hence，he took the method of heat-clearing and tonifying，frequently combined with herbs resolving stasis and eliminating dampness in treatment for.Henoch-Schonlein purpura nephritis