Objective To observe plasma MIF and TNF-α levels in patients with ACS and explore their clinical significance in ACS.Methods 58 patients with ACS were recruited,including 30 patients with acute myocardial infarction(AMI)and 28 patients with unstable angina(UA),24 cases who had normal coronary angiography also were recruited as control group.The degree of coronary artery stenosis was determined by Gensini’s scores system.Plasma MIF level was measured by ELISA and TNF-α was measured by radioimmunoassay(RIA) method.Results The levels of MIF and TNF-α in ACS group were significantly higher than those in control group(P<0.01),and they were higher in AMI subgroup than in UA subgroup(P<0.01).The levels of MIF、TNF-α in ACS group were correlated with the degree of coronary artery stenosis(P<0.05).Conclusions Increased MIF and TNF-α could not only reflect the severity of ACS,but also predict the potential risk and the degree of coronary artery stenosis in the initial stage of ACS.