Aim To investigate the changes of plasma matrix metalloproteinase-2(MMP-2),tissue inhibitor of matrix metalloproteinase-2(TIMP-2) level and MMP-2/TIMP-2 ratio in patients with different types of coronary heart disease(CHD),and discuss clinical significances. Methods A total of 118 patients were divided cardioangiographically and clinically into following groups: acute coronary syndrome(ACS) group with 49 cases including unstable angina pectoris(UAP) subgroup with 30 cases and acute myocardial infarction(AMI) with 19 cases;non-ACS group with 44 cases including stable angina pectoris(SAP) with 23 cases and chronic total occlusion of coronary artery(CTO) with 21cases;and normal coronary artery group as a control with 25 cases.The plasma levels of MMP-2 and TIMP-2 were assayed by enzyme-linked immunosorbent assay(ELISA). Results Compared with normal coronary artery group,remarkably elevated plasma MMP-2 level was observed in ACS group and non-ACS group(both P<0.05),and the increasing of MMP-2/TIMP-2 ratio was significant(P<0.01) in both ACS and non-ACS groups.MMP-2 and TIMP-2 level and MMP-2/TIMP-2 ratio were obviously higher in ACS group than that in non-ACS group(P<0.05 or P<0.01).MMP-2 level was increasing more in UAP subgroup(P<0.05),AMI subgroup(P<0.05),and CTO subgroup(P<0.01) compared with normal coronary artery group,respectively.Comparison between normal coronary artery group with each subgroup,concentration of TIMP-2 was higher in UAP subgroup(P<0.05),SAP subgroup(P<0.001),and CTO subgroup(P<0.01),respectively. Conclusion The developing of atherosclerosis plaque was associated with plasma MMP-2 level,TIMP-2 level and imbalance of MMP-2/TIMP-2 proportion in CHD patients.The increased MMP-2 level and imbalance of MMP-2/TIMP-2 proportion in patients with CHD suggested instability of atherosclerotic plaque,and might be viewed as one of predictable biomarkers for occurrence of ACS event.