Objective To explore the application of gemstone spectral CT cerebral perfusion in the diagnosis of patients with cerebrovascular diseases. Methods A total of 110 patients with cerebrovascular diseases who were diagnosed with “gold standard” digital subtraction angiography (DSA) and diagnostic criteria of cerebrovascular disease were selected and examined by common CT and gemstone spectral CT cerebral perfusion. The coincidence rate of common CT diagnosis and gemstone spectral CT diagnosis was analyzed, and the suspected cerebrovascular stenosis (using the SAMUELS standard for the calculation of intracranial vascular stenosis) by common CT and cerebrovascular stenosis by gemstone spectral CT were compared, and the detection situations of arterial plaque were compared between common CT diagnosis and gemstone spectral CT. Results There were no significant differences in the detection rates of cerebral hemorrhage and cerebral infarction by gemstone spectral CT (P>0.05), and the detection rate of aneurysms with 100.00% by gemstone spectral CT was significantly higher than that by common CT (P<0.05), and the number of patients with vascular stenosis by SAMUELS standard in gemstone spectral CT was more than that in common CT, and the accuracy in the diagnosis of different degrees of vascular stenosis was higher than that of common CT (P<0.05), and the total number of detected plaques by gemstone spectral CT was much higher than that by common CT (79.09% vs 21.82%) (P<0.05). Conclusion Gemstone spectral CT cerebral perfusion has significant diagnostic effects on patients with cerebrovascular diseases.