Aim To explore the relationship between uremia rats aortic stiffness and expression of matrix metalloproteinase-2 （MMP-2） in aorta and the mechanism involved. Methods 20 rats were divided into three groups randomly, as normal control group, chronic renal failure group and chronic kidney failure group with vascular calcification. Normal control group （methyl cellulose）, chronic renal failure group （methyl cellulose＋adenine sulphate）, chronic renal failure group with vascular calcification （adenine sulphate＋calcitriol）. The aortic pulse wave velocity （PWV） was measured after 8 weeks, expression of core binding factor alpha 1 （Cbfα1） and MMP-2 mRNA were determined by reverse transcription polymerase chain reaction （RT-PCR） and MMP-2 protein was detected by immunohistochemistry. Von Kossa was used to test the calcification of aorta and quantified by aortic calcium content. The alteration of aortic stiffness was tested by Elastica Van Gieson （EVG）. Results Aortic PWV, expression of aorta Cbfα1, MMP-2 mRNA and protein, aortic calcium content in chronic renal failure group with vascular calcification are all higher than those in chronic renal failure group （P<0.05）.Aortic PWV, expression of aorta Cbfα1, MMP-2 mRNA and protein in chronic renal failure group are higher than those in normal control group （P<0.05）. Aortic PWV shows a positive correlation to the expression of MMP-2 in aorta （r＝0.754, P＝0.02）. Conclusion One of the mechanisms of decreased vascular elasticity function in rats with chronic kidney disease is elastin degradation caused by increasing expression of MMP-2 in the artery wall, while the late vascular calcification is also involved.