Objective To investigate the effect of degree of lower extremity arterial disease in treatment of diabetic foot ulcer with platelet-rich gel. Methods A total of 129 patients with diabetic foot ulcer were selected as the study objects. According to ankle-brachial index and lower extremity artery vascular ultrasound results, 49 cases were divided into mild group (49 cases), moderate group (44 cases) and severe group (36 cases). All patients in three groups were given conventional treatment combined with platelet-rich gel therapy. The changes of ulcer area and granulation area before and after treatment in three groups were compared. Results The ulcer area and its difference value before and after treatment among the three groups were statistically significant (P<0.05). The granulation tissue area and its difference value before and after treatment among the three groups showed statistical significance (P<0.05). The difference value in ulcer area was positively correlated with ankle-brachial index (r=0.392, P<0.001), and negatively correlated with diabetes course (r=-0.420, P<0.001); the difference value in granulation area was positively correlated with ankle-brachial index (r=0.406, P<0.001) and negatively correlated with diabetes course (r=-0.375, P<0.001). Conclusion The more severe the lower extremity artery lesionsis, the worse the therapeutic effect of platelet-rich gel on diabetic foot ulcer will be.