Aim To explore the predictive value of the newly defined C-reactive protein (CRP) to albumin ratio (CAR) in determining the degree of coronary artery stenosis compared with other inflammatory markers, such as neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), monocyte to lymphocyte ratio (MLR). Methods Patients with acute myocardial infarction (n＝203) and patients with non-AMI coronary heart disease (n＝103) hospitalized in the Department of Cardiology of the People's Hospital of Xinjiang Uygur Autonomous Region from January 1,8 to January 1,0 were included. According to the syntax score, AMI group was divided into two groups:low Syntax score group (Syntax score≤22 points, n＝124) and high Syntax score group (Syntax score≥23, n＝79). CAR, NLR, PLR and MLR were measured, the levels of CAR, NLR, PLR and MLR in each group were compared, and the relationship between the levels of CAR, NLR, PLR and MLR and the degree of coronary artery stenosis was evaluated.. Results The levels of CAR, NLR, PLR and MLR in AMI group were significantly higher than those in non-AMI group (P＜0.001). Correlation analysis showed that CAR was significantly correlated with Syntax score (r＝0.634, P＜0.001), while NLR, PLR and MLR were low correlated with Syntax (r＝0.304, P＜0.001; r＝0.463, P＜0.001; r＝0.344, P＜0.001). Logistic regression analysis showed that CAR level was the only independent risk factor for high Syntax score (OR＝1.8,5%CI:1.004～1.161, P＝0.038). Conclusion The level of inflammatory marker CAR is correlated with the degree of coronary artery stenosis, which can be used as a reliable marker to predict the degree of coronary artery stenosis in AMI patients.