Aim To examine the effects of oxidized low density lipoprotein (ox-LDL) on expressions of matrix metalloproteinase-2 (MMP-2) and MMP-9 in cultured rat vascular smooth muscle cells (VSMCs), and explore the relation between the migration and proliferation of VSMCs and the expression activity of these two genes. Methods Northern blot, Dot blot, Western blot and SDS-PAGE containing gelatin were used to detect MMP-2 and MMP-9 mRNA expression, protein synthesis and enzyme activities. Results The mRNA expressions, protein levels and enzyme activities of MMP-2 and MMP-9 significantly increased after VSMCs were stimulated by 10 mg/L ox-LDL for 24 h. When the concentration of ox-LDL were enhanced to 50 mg/L, different effects were exerted on MMP-2 and MMP-9. The levels of MMP-9 were still higher than control group and as the same as the group of 10 mg/L ox-LDL. However, the expression of MMP-2 decreased markedly at the same condition. Conclusion Ox-LDL could increase the expression activities of MMP-2 and MMP-9 and the degradation of ECM.