Objective To analyze the value of digital subtraction CTA in the diagnosis of spontaneous subarachnoid hemorrhage (SAH). Methods A total of 200 patients with spontaneous SAH who were admitted to the hospital from March 2017 to March 2018 were selected as the study subjects. Three-dimensional digital subtraction angiography (DSA) and digital subtraction CTA (subtraction CTA) were performed. The image quality and display effect were compared between subtraction CTA and DSA. With DSA as the golden standard, the diagnostic efficiency of subtraction CTA was analyzed and the measured data of aneurysms were compared. Results There were 157 cases of aneurysms, 10 cases of cerebral arteriovenous malformations (AVM), 5 cases of Moyamoya disease and 28 negative cases detected by DSA. 147 cases of aneurysms, 10 cases of AVM, 5 cases of Moyamoya diseaseand 38negative cases were detected by CTA.4 cases of aneurysmswere misdiagnosedand 14 cases were missed. There was no significant difference in the image quality between subtraction CTA and DSA (P>0.05). The sensitivity, specificity and accuracy of subtraction CTA in the diagnosis of SAH were 91.86%, 85.71% and 91.00%, respectively. There was no significant difference in the diameter of aneurysms and tumors measured by CTA and DSA (P>0.05). Conclusion Digital subtraction CTA is of great value in the diagnosis of spontaneous SAH. It can be used as one of the commonly used diagnostic method.