Objective To investigate the correlation of triglyceride glucose product index(TyG index)with the diagnosis of coronary heart disease(CHD)and the severity of coronary stenosis.Methods A total of 404 patients who received coronary angiography for the first time in Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine with unexplained chest pain from December 2021 to October 2022 were included.All subjects were divided into CHD group(n=216)and non-CHD group(n=188).General clin-ical data,laboratory information and coronary angiography results of all participants were collected.The CHD group(n=123)and the non-CHD group(n=123)were obtained after the propensity score matching(PSM).Patients in CHD group were further divided into low Gensini score(Gensini score＜35,n=59)group and high Gensini score(Gensini score ≥ 35,n=64)group according to the me-dian Gensini score.The differences among groups were compared and the relation between TyG index and the severity of coronary artery stenosis was analyzed.Then the predictive value of TyG index for CHD and the severity of coronary lesion was evaluated by Logistic regres-sion and receiver operating characteristic(ROC)curve.Results After PSM,the differences in TyG index,TG,FPG,HDL-C in CHD group were statistically significant compared with the non-CHD group(P＜0.05).Multivariate Logistic regression analysis showed that the TyG index was an independent risk factor for CHD.Spearman correlation analysis showed that the TyG index was positively correlated with the Gensini score(r=0.618,P＜0.001).The ROC curve analysis showed that the area under the curve(AUC)of the TyG index predicting a high Gensini score was 0.873(95％CI:0.802-0.943,P＜0.001).A cut-off value was 7.08,and the sensitivity and specificity were 95.2％and 67.3％,respectively.Conclusion TyG index can be used as an independent risk factor for CHD,and has certain predictive value for the severity of coronary stenosis.