To analyze the composition principles of prescription for cancerous pain. Methods: Prescriptions used for cancerous pain on CNKI were retrieved, and the relevant data were entered into the TCM inheritance support system to conduct principle analysis and hierarchical clustering to analyze composing principles. Results: Based on the analysis of 92 cases of prescriptions, including 184 kinds of herbs, the frequency of each herb and association rules among herbs included in the database were computed, and 7 core combinations and 7 new prescriptions were mined from the database. Conclusion: The prescriptions for cancerous pain were based on the principle of “strengthening body resistance and eliminating evil”, with the application of deficiency-tonifying, blood-activating, and heat-clearing drugs.