【Abstract】 Objective To discuss the value of matrix metalloproteinase2，9 in diagnosing and predicting acute coronary syndrome (ACS). Methods 128 ACS patients treated in our hospital were selected to observation group，and 89 non heart disease patients were selected to control group. The two groups were taken fasting blood samples on the day before coronary angiography to calibrate serum levels of MMP2 and MMP9. All of patients were followedup of 6 months after visiting. Cardiac death，coronary artery bypass grafting and percutaneous coronary angioplasty were recorded as cardiovascular events thus the followup would be terminated. Results The levels of MMP2 and MMP9 in observation group were exceeded the levels in control group and the difference was statistically significant（P＜005）. End points of response rate was positively associated with the concentration of MMP2 and MMP9（P＜001）. Conclusion Serum levels of MMP2 and MMP9 have important value in the diagnosis and prognosis in patients with acute coronary syndrome.