Objectives To investigate the value of pregnancy-associated plasma protein-A (PAPP-A)and matrix metallo proteinase-9 (MMP-9) in the diagnosis and outcomes evaluation of acute coronary syndrome(ACS) patient. Methods 100 ACS patients were divided into UAP group (64 cases ) and AMI group (36 cases), and 50 healthy cases served as control group.The levels of PAPP-A, MMP-9, Hs-CRP, CK-MB and cTnI were obtained. The ACS patients with normal CKMB and cTnI concentration were followed up. During 6 months, the total rates of major cardiovascular events(MACE) were recorded. Results Compared to control group, the PAPP-A, MMP-9, Hs-CRP, CK-MB, cTnI levels of ACS patients were significantly increased (P＜0.01 ), but the levels of PAPP-A, MMP-9 did not correlate well with CK-MB and cTnI. The ACS patients with normal CK-MB and cTnI concentration were followed up 6 months, the levels of PAPP-A, MMP-9 were significantly associated with the MACE ( P＜0.01 ). Conclusions The levels of PAPP-A, MMP-9 of ACS patients were not associated with myocardial ischemic necrosis,but could serve as predictor of unstable atherosclerotic plaque, and as valuable index for prognosis monitoring in ACS patients.