The aim of this study is to observe the clinic result of alprostadil injection for diabetes mellitus patients with lower limb vessels disease which was evaluated by color Doppler ultrasonography. 650 cases of diabetes mellitus with lower limb vessels disease treated by alprostadil injection and followed up by color Doppler ultrasonography to observe the blood flow dynamics inside the vessels and the range of color Doppler ultrasonography. After treatment by alprostadil injection, the interior diameter of vessels increased, blood flow increased and color Doppler ultrasonography spectrum narrowed with relief of clinic symptom. Thus, color Doppler can make a rapid and exact diagnosis to the vessel diseases, and can give a guide to the prognosis and nursing.