Objective:To explore the correlation among plasma levels of fibrinogen (Fg) ,D-dimer (DD) and antithrombin III (ATIII ) and carotid atherosclerosis (CAS) in AMI patients .Methods:A total of 147 AMI patients treated in our de‐partment from Jan 2012 to Dec 2014 were enrolled as AMI group ,another 120 patients without myocardial infarction (MI) were treated as control group .According to ACS severity ,AMI group was further divided into normal group (n=22) ,mild group (n=30) ,moderate group (n=40) and severe group (n=55) .Plasma levels of Fg ,DD and ATIII ,and carotid inti‐ma-media thickness (IMT) were measured and compared among all groups .Results:Compared with control group ,there were significant rise in plasma levels of Fg [ (3.12 ± 0.87) g/L vs .(5.01 ± 1.38) g/L] ,DD [ (317 ± 50)μg/L vs .(1530 ± 218)μg/L] and carotid IMT [(0.86 ± 0.41) mm vs .(1.12 ± 0.29) mm] ,and significant reduction in plasma AT Ⅲ level [ (87 ± 18)% vs .(76 ± 19)% ] in AMI group , P<0.01 all. Compared with normal group ,there were significant rise in plasma levels of Fg and DD ,and significant reduction in plasma ATIII level in moderate group and severe group , P<0.05 or <0.01. Spearman correlation analysis indicated that plasma Fg and DD levels were significant positively correlated with CAS severity (r=0.426 ,0.535 ,P<0.01 both) ,ATIII level was significant inversely correlated with CAS severity in AMI patients ,(r= -0.438 ,P=0.005) .Multi-factor Logistic regression analysis indicated that plasma Fg and DD levels were independent risk factors for MI (OR=2.836 ,2.231 , P<0.01 both) ,and plasma ATIII level was independent protective factor for MI (OR=0.899 , P=0.014 ) .Conclusion:Plasma Fg and DD levels are independent risk factors for MI and plasma ATIII level is independent protective factor for MI .