Aim To study arteriosclerosis induced by large dose of vitamin D3(VitD3)and its mechanism in mouse.Methods Forty Kunming mouse were randomly divided into three groups including control group,model group and normal VitD3 group,with sixteen in the forner two groups,in which male and female were eight equally and eight in the last group.Then mouse in model group were given forty units of VitD3 for three days and observed for forty-two days.Sections were made for aortic arch and stained by hematoxylin and eosin,thoracic aortawere stained by Von kossa and the percentage of calcificational areas was counted,the content of Ca and P was measured by ICP.Results The media of aorta was seriously calcified in VitD3 model group compared with control group,phenotype of smooth muscle cell in media of aorta have changed to another phenotype which was suspected for chondrocyte,percentage of calcificational areas in model group was remarkably higher than in control group(P<0.01).The content of Ca and P for abdominal aorta was higher in model group than in control group(P<0.05).Conclusion Large dose of VitD3 could lead to the serious calcification located in media of aorta in mouse,and the vascular smooth muscle cell coverted to analogical chondrocyte.The mechanism was connected to that large dose of VitD3 which induces the convertion of vascular smooth muscle cell to analogical chondrocyte and simultaneously leads to the massive deposition of Ca and P in blood vessel.