Abstract: Objective: To investigate the relationship between the levels of plasma homocysteine(Hcy),matrix metalloproteinase-9 (MMP-9) and carotid atherosclerosis(CAS) in patients with ischemic cerebrovascular disease(IVCD). Methods: Two hundred and forty patients with IVCD (IVCD group) and 236 patients without cerebrovascular diseases (control group) received carotid ultrasonograph to detect the intima-media thickness(IMT) of the carotid artery. The correlation analysis was made between the levels of Hcy,MMP-9 and CAS plaque and its degree. Results: The levels of Hcy and MMP-9 in IVCD group were significantly higher than those in control group(P < 0.01); the levels of Hcy and MMP-9 in IVCD group with carotid atherosclerotic plaque were significantly higher than that in control group(P < 0.01); the IMT was positively correlated with the level of Hcy and MMP-9 in IVCD group(P < 0.05); the degree of CAS was positively correlated with the level of Hcy and MMP-9 in IVCD group(P < 0.05); the level of Hcy was positively correlated with that of MMP-9 in IVCD group(P < 0.01). Age,hypertension,hyperlipidemia,diabetes,smoke,drink and coronary artery disease were important risk factors for formation of CAS plaque. Conclusions: The formation of CAS plaque may be closely associated with the level of Hcy and MMP-9 in patients with IVCD. There is higher degree of CAS,the more correlation between CAS and Hcy or MMP-9. The levels of Hcy and MMP-9 in patients with IVCD may reflect the character and stability of carotid artery plaque,and they can be important indicators about the severity of IVCD for clinical practice.