To research the TCM pattern of irritable bowel pattern (IBS). Methods: We extracted data of symptoms, tongue manifestation and pulse condition from TCM epidemiology research of 309 cases of IBS, then used the factor analysis and cluster analysis on 88 variables. Results: It broken down to 12 TCM patterns, i.e. pattern of liver depression and spleen deficiency, pattern of liver qi invading the Stomach, pattern of dual deficiency of the heart and spleen , spleen-kidney yang deficiency pattern, pattern of ascendant hyperactivity of liver yang , pattern of depressed gallbladder with harassing phlegm, spleen deficiency pattern , pattern of liver depression and qi stagnation , liver qi invading the spleen, pattern of dampness-heat in the spleen and stomach, large intestinal dampness-heat pattern, qi stagnation of the spleen and stomach. Conclusion: The research reflects the potential factors which determines the correlation between the variables, and provides some objective clinical diagnosis and treatment basis.