Objective.. To investigate the application of entropy partition method （EPM） for studying the diagnostic criteria of Traditional Chinese Medicine （TCM） syndrome. Methods.. A clinical epidemiological survey was conducted in 400 patients with vascular endothelial dysfunction and the EPM was adopted to extract the TCM syndrome elements of ＂stagnancy of collateral-Qi in a deficiency condition＂, the correlation degree between each symptom of ＂stagnancy of collateral-Qi in a deficiency condition＂ was calculated and the diagnostic threshold of vascular endothelial dysfunction was established. The sensitivity, specificity and accuracy of the EPM-associated diagnostic criteria were assessed by comparing with those of clinical epidemiology. Results： The diagnostic criteria of ＂stagnancy of collateral-Qi in a deficiency condition＂ in vascular endothelial dysfunction established with EPM had a satisfactory diagnostic efficiency. Conclusion： EPM for complex system is suitable for studying the diagnostic criteria of TCM syndrome. EPM is a scientific and strict method and has great value in clinical practice.[著者文摘]