Objective: To analyze composition principles of the prescriptions for the treatment of atrophic lung disease. Method: prescriptions for atrophic lung disease are collected

sorted and entered into the TCM inheritance system (V1.1) to analyze the composition principles by the methods of entropy and apriori. Result: Based on the analysis of 181 cases of prescriptions

twenty-three medications with more than 10 frequencies are mined from the database. Composition principles are obtained with apriori method: forty-two frequently used herbal pair (support≤13); thirty-five core combinations with 3 medications (support ≤8); 8 core combinations with 4 medications (support ≤6); also the association principles for those medications in the prescriptions are analyzed (support≤10

confidence≤0.6). Principles are obtained with entropy: thirty-two core combinations with implicit rules of 3 medications; nine new core combinations 9 new prescriptions are found by hierarchical clustering method. Conclusion: TCM inheritance system(V1.1) is a useful tool to analyze the composition principles of prescriptions.