Objective To investigate the application of 64-slice spiral CT angiography (CTA) in diabetic lower extremity vascular disease. Methods A total of 102 cases of patients with diabetes mellitus (a total of 1850 vessels) who underwent lower extremity vascular examination from May 2017 to May 2018 were analyzed retrospectively. All patients were given CTA and color Doppler ultrasound. The digital subtraction angiography (DSA) results were used as the gold standard to compare the sensitivity, specificity, accuracy and Kappa value of the two methods. The degree of lower extremity vascular disease of diabetic patients detected by CTA and DSA was compared. The distribution of vascular disease was recorded by CTA. Results Compared with the gold standard (DSA), the sensitivity, specificity, accuracy and the Kappa value of CTA in lower extremity vascular disease were 0.961, 0.792, 0.916 and 0.778, which were greater than those of color Doppler ultrasound with 0.849, 0.566, 0.773 and 0.417. There was no significant difference between CTA and DSA in the detection rates of mild stenosis, moderate stenosis, severe stenosis and occlusion of lower extremity vascular disease in diabetic patients (P>0.05). By study, 31.37% (32/102) patients showed popliteal artery stenosis or occlusion, and 29.41% (30/102) patients showed femoral artery stenosis or occlusion, and 12.75% (13/102) patients showed abdominal aorta stenosis or occlusion, and 14.71% (15/102) patients showed stenosis or occlusion of calf artery, and 11.76% (12/102) patients showed stenosis or occlusion of iliac artery. Conclusion 64-slice CTA is reliable for the detection of lower extremity vascular disease in diabetic patients, and it has high sensitivity and specificity, and can accurately reflect the vascular lesions of patients.