Aim To investigate the correlation between insulin resistance (IR) and degree of coronary artery lesion in patients with coronary heart disease (CHD) and impaired glucose tolerance (IGT). Methods 152 CHD patients with IGT, and 35 CHD patients with non-IGT (control group) were enrolled in this study. IR index (HOMA2-IR) was determined by HOMA2 method. Gensini score system was used to assess the degree of coronary artery stenosis quantitatively, and the type B₂/C lesions were defined as complex lesions of the coronary artery. Taking the HOMA2-IR quartile as the cutoff point, 152 CHD patients with IGT were divided into 4 groups:the first quartile group (n＝38), the second quartile group (n＝38), the third quartile group (n＝38), the fourth quartile group (n＝38). Baseline data and the results of coronary angiography were compared among the five groups. Results 2 hour postprandial blood glucose (2hPBG), glycosylated hemoglobin A1 (HbA1c), fasting insulin and Gensini score increased gradually in the 5 groups, the difference was statistically significant (P＜0.01). Coronary multiple lesions and B₂/C lesions in fourth quartile group were significantly higher than those in first quartile group and control group (P＜0.05). Correlation analysis showed that Gensini score was positively correlated with HOMA2-IR (r＝0.712, P＜0.001). Multivariable stepwise regression analysis showed that HOMA2-IR, HbA1c and 2hPBG were the independent risk factors affecting the degree of coronary artery stenosis. Logistic regression analysis showed that HOMA2-IR was an independent risk factor for multiple lesions and B₂/C lesions. Conclusion IR is an important index reflecting the degree of coronary artery stenosis in patients with CHD and IGT.