Aim To investigate the changes of vascular endothelial function and carotid artery intima-media thickness (IMT) in patients with diabetic arterial occlusion of lower extremities (DAO). Methods Using high resolution ultrasound, endothelium-dependent dilation (EDD), endothelium-independent dilation (EID) and IMT were measured in 60 patients with DAO (20 of 1st stage, 20 of 2nd stage and 20 of 3rd stage). 20 healthy people were respectively observed as the control group. Changes of vascular tension factors as endothelin-1 (ET-1), thromboxane B2 (TXB2), nitric oxide (NO) and 6-keto-prostaglandin F1α(6-Keto-PGF1α) were also be studied. Results The results show that EDD of the branchial artery in patients with DAO was reduced significantly compared with those healthy control and EDD has significantly characteristic changes in different stage (8.39%±1.62%, 6.22%±1.27%, and 4.02%±2.35% vs 10.58%±2.92%, P<0.01). EID of the branchial artery in patients of 3rd stage was also lower than those control (9.07%±6.36% vs 15.17%±2.71%, P<0.01). IMT of patients of 2nd and 3rd stage were significantly higher than those of healthy control group (1.06±0.06 mm and 1.12±0.04 mm vs 0.87±0.04 mm, P<0.01). Vascular contractile factors as ET-1 and TXB2 levels were higher than those in healthy control (P<0.01), while vascular dilatory factors as NO and 6-Keto-PGF1α were declined significantly than those in healthy control (P<0.01). Conclusions Vascular endothelial dysfunction may play an important role in the pathogenesis of DAO. Vascular endothelial function and IMT can be used to monitor patients condition.