Abstract: AIM To investigate the relationship between left ventricular ejection fraction( LVEF) and angiographic characteristics of acute coronary syndrome( ACS). METHODS A total of 647 patients with ACS were divided into two groups according to Gensini score. Three hundred and twenty-eight patients were in group A with Gensini ≥45%; 319 were in group B with Gensini < 45%. Baseline characteristics were analyzed between groups. Severity of coronary atherosclerosis was defined by the Gensini score system. Statistical methods including one-way ANOVA,Kruskal-Wallis test,Spearman correlation analysis and multivariate stepwise linear regression analysis were employed to explore the relationship between EF and Gensini score. RESULTS In group A,FBG,Hb A1 c,WBC and LA were increased.LVEF,HDL and calcium ion were decreased. Spearman correlation indicated that Gensini score significantly correlated with the LVEF( r =- 0. 28,P < 0. 01). The result from the multivariate stepwise linear regression analysis showed that LVEF( β =- 0. 313,P < 0. 01) was significantly and independently associated with the Gensini score. CONCLUSION EF is significantly and positively associated with Gensini score in patients with ACS.