Objective:To evaluate the association of 25-hydroxyvitamin D3[25 (OH)D3] with macroangiopathy in type 2 diabetes mellitus (T2DM). Methods:There were 189 T2DM patients and 100 controls in study. The patients were divided into two groups (T2DM group and T2DM complicated with macroangiopathy group) based on their clinical features. Clinical data,metabolic indices and serum 25(OH)D3 levels were detected compared among all groups. According to the level of 25 (OH)D3,all patients were divided into 3 groups,low 25 (OH)D3 group,middle 25 (OH)D3 group and high 25 (OH)D3 group. The relevance of 25 (OH)D3 and other parameters were analyzed by Pearson correlation analysis. Results:The serum 25 (OH)D3 level in T2DM group or T2DM complicated with macroangiopathy group was significantly lower than that in the control group(P < 0.05),and the serum 25 (OH)D3 level in T2DM complicated with macroangiopathy group was significantly lower than that in the T2DM group (P < 0.05). From high 25(OH)D3 level group to low 25 (OH)D3 level group,the prevalence of macroangiopathy were increased from 14.29%,25.40% to 48.73%,respectively. The macroangiopathy prevalence in T2DM of low 25 (OH)D3 level group was significantly higher than the other two groups with high 25 (OH)D3 level(P < 0.05). Conclusion:The serum 25(OH)D3 level was negatively related with macroangiopathy in T2DM. The decreased serum levels of 25(OH)D3 maybe increase risk of macroangiopathy.