Diabetic neuropathy (DN) is, at least in part, associated with the functional attenuation of vasa nervorum, the microvascular structure of peripheral nerves. Microvascular imaging options for vasa nervorum still remain limited. In this work, optical microangiography (OMAG), a volumetric, label-free imaging technique, is utilized for characterizing, with high resolution, blood perfusion of peripheral nerve in diabetic mice. We demonstrate that OMAG is able to visualize the structure of microvasculature and to quantify the changes of dynamic blood flow and vessel diameters during administration of vessel stimulant in both diabetic and normal mice. The results indicate the potential of OMAG to assess the blood supply of nerve involved in the pathology and treatment of DN.