Objective To investigate the application effect of CT angiography (CTA) in diagnosis of lower extremity arterial staging and lower extremity arterial stenosis in diabetic patients. Methods 89 patients with diabetic lower extremity arterial disease diagnosed in our hospital from January 2015 to August 2017 were selected. All patients underwent CTA and digital subtraction angiography (DSA). The CTA and DSA images of 89 patients were reconstructed and evaluated by two experienced radiology diagnosticians. Using DSA test results as the standard reference, the sensitivity, specificity, accuracy, and the application value of CTA in the diagnosis of lower extremity arterial stenosis were analyzed. Results The consistency between CTA and DSA test results was similar. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of CTA in detecting the artery stenosis degree above the knee segment were 97.23%, 97.15%, 97.13%, 94.02% and 97.89%, Kappa=0.945. Those below knee segment were 96.12%, 92.05%, 94.13%, 92.22% and 9634%, Kappa=0.875. Those of pedal artery were 69.21%, 90.95%, 89.03%, 72.34% and 88.86%, Kappa=0.657. Conclusion CTA diagnosis of lower extremity arterial disease in diabetes can provide an intuitive, comprehensive, clear and accurate display of the lesions, which is helpful for the radiologist to accurately classify the degree of stenosis, and provides important clinical preoperative evaluation and screening for diabetic arterial disease of the lower limbs.