Objective To investigate the correlation between glucose variability and coronary stenosis in type 2 diabetes mellitus (T2DM) combined with coronary heart disease (CHD) patients.Methods Eighty patients with T2DM who had undergone coronary angiography were selected.According to the result of coronary angiography,the patients were divided into 2 groups:48 T2DM combined with CHD patients as CHD group,and 32 T2DM combined without CHD patients as control group.All patients underwent continuous glucose monitoring (CGM) for 72 h,and the mean blood glucose (MBG),standard deviation of blood glucose (SDBG),daily mean amplitude of glycemic excursion (MAGE),absolute means of daily differences (MODD),largest amplitude of blood glucose excursion (LAGE) and mean postprandial glucose excursion (MPPGE) were computed.The risk factor of coronary stenosis (using Gensini score) was analyzed.Results The LAGE,SDBG,MAGE,MPPGE,MODD in CHD group were significantly higher than those in control group:(11.4 ± 3.6) mmol/L vs.(8.2 ± 1.9) mmol/L,(3.4 ± 1.4) mmol/L vs.(1.9 ± 0.6) mmol/L,(7.1 ± 2.7) mmol/L vs.(4.8 ± 1.4) mmol/L,(6.6 ± 1.8) mmol/L vs.(4.6 ± 1.5) mmol/L,(3.3 ± 1.2) mmol/L vs.(2.5 ± 0.9) mmol/L,and there were statistical differences (P ＜ 0.05).There was no statistical difference in MBG between CHD group and control group:(10.2 ± 2.8) mmol/L vs.(9.3 ± 2.2) mmol/L,P ＞ 0.05.The Pearson correlation analysis result showed that the MPPGE,MODD and LAGE had positive correlation with Gensini score (r =0.509,0.357 and 0.338;P ＜ 0.05);and the LVEF had negative correlation with Gensini score (r =-0.372,P ＜ 0.05).Conclusions Glucose variability in patients with T2DM combined with CHD is markedly enhanced.MPPGE,MODD and IAGE are positively correlated with the severity of coronary stenosis.