Objective To construct a diagnostic model based on the information of the TCM four diagnoses in hyperactive liver yang syndrome in patients with essential hypertension.Methods Syndromic investigation was carried out in patients with essential hypertension in some hospitals in Fujian and Beijing,and diagnostic information such as age,gender,symptoms,tongue and pulse were collected.On the basis of statistical analysis,this study adopted C5.0,CRT,CHAID and QUEST decision tree models respectively.After evaluating the stability and performance consistency of the models,the accuracy of the models was measured by diagnostic rate,and the optimal model of hyperactivity of liver yang in essential hypertension was selected.Results Totally 533 patients with essential hypertension were included,including 198 patients with hyperactive liver yang syndrome and 335 patients without hyperactive liver yang syndrome.The diagnostic rates of the four models were 75.2%,66.2%,67.7%and 65.0%,respectively.The diagnostic efficiency of C5.0 was better than that of CRT,CHAID and QUEST models."Aggravation after emotional excitement,poor complexion,string-like pulse,irritability,head swelling pain,bitter mouth,heavy pulse,fatigue,dark tongue,irritability,dizziness,thin pulse,yellow fur"could be regarded as the specific items of the syndrome model of hyperactive liver yang in essential hypertension.Conclusion The C5.0 decision tree model can clearly and intuitively identify the hyperactive liver yang syndrome in essential hypertension patients based on clinical TCM four diagnostic information data,and summarize diagnostic rules.