Objective To investigate the correlation of hs-CRP and systemic immunoinflammatory index(SII)with the severity of coronary artery stenosis in elderly T2DM patients.Methods A retrospective trial was conducted on 158 elderly T2DM patients admitted to the Affiliated Hospi-tal of Xuzhou Medical University from August 2021 to August 2023.According to the results of coronary angiography,they were divided into mild(Gensini score≤60,79 cases)and severe steno-sis groups(＞60,79 cases).Spearman correlation analysis and logistic regression analysis were ap-plied to analyze the correlation and the risk factors for severe stenosis.Results Significantly high-er hs-CRP and SII were observed in the severe stenosis group than the mild stenosis group(P＜0.01).Hs-CRP,SII,glycosylated hemoglobin,neutrophils,hsTNT,NLR,and PLR were positively correlated with Gensini score(r=0.424,P＜0.01;r=0.367,P＜0.01;r=0.207,P＜0.01;r=0.259,P＜0.01;r=0.187,P＜0.05;r=0.317,P＜0.01;r=0.256,P＜0.01),and the course of T2DM was negatively correlated with Gensini score(r=-0.224,P＜0.01).Multivariate logistic regression showed that hs-CRP and SII were independent risk factors for severity coronary artery stenosis in elderly T2DM patients(OR=3.191,95％CI:1.847-5.513,P=0.000;OR=1.006,95％CI:1.004-1.009,P=0.000).Conclusion Elderly T2DM patients have higher levels of hs-CRP and SII,which may be independent risk factors for the pathogenesis of coronary stenosis.