Abstract: Objective To explore the relationship between neutrophil-to-lymphocyte ratio(NLR)with totally occluded lesion and left ventricular function in acute coronary syndrome(ACS). Methods One hundred and twenty patients in cardiology intervention treatment center of Chinese PLA General Hospital who were diagnosed as ACS and underwent coronary angiography were randomly selected.Clinical data about patients were obtained from the medical record, and patients were divided into two groups according to NLR, the correlation of various factors were compared and analyzed. Results The differences of totally occluded lesion, left ventricular ejection fraction(LVEF), creatinine and lipoprotein(a)in different groups were statistically significant. Conclusion Elevated NLR is related with injured left ventricular function and totally occluded lesion, and NLR can be used for cardiovascular risk stratification.