Objective: To explore the relation of the level of serum matrix metalloproteinase-9( MMP-9), and artery elasticity function in diabetic patients. Methods: 34 healthy persons were enrolled in the control group, defined as the group A .77 diabetic patients were enrolled and divided into two groups: group B, 32 diabetic patients with normal thickness of carotid artery intima; group C, 45 diabetic patients with thickened carotid intima or atheromatousSplaque. The levels of MMP-9 were measured by means of (enzyme linked immunosorbent assay)ELISA. The blood vessel elastic modulus, including stiffness( β), pressure-strain elastic modulus ( Ep), arterial compliance( AC), increase index ( AI) , parameter ( PWVβ) were calculated by echo-tracking technique. Then the correlation between serum MMP-9 level and carotid artery elasticity index were analyzed. Results: The value of Ep, AI, PWVβ and the level of serum MMP-9 in group B were higher than those in healthy group,while the level of AC was lower than that in healthy group( P＜0.05). The value of β, Ep, PWVβ and the level of serum MMP-9 in group C were higher than those in group B; while the level of AC inwas lower than that in group B( P＜ 0.05) . The level of serum MMP-9 was related with β and PWVβ(P＜0.05) in group B, while these value were Ep, β, AI, PWVβ in group C. Conclusion: As it exist the correlation between artery elasticity function and serum MMP-9 level, the level of MMP-9 can be considered as a sensitive index to detect the atherosclerosis in early stage in diabetic patients.