Objective To explore the diagnostic value of whole brain CT perfusion imaging (CTP) and CT angiography (CTA) of 256-slice multi-slice spiral CT (MSCT) in patients with acute cerebral infarction. Methods The clinical data of 48 patients with acute cerebral infarction admitted to our hospital from June 2016 to June 2018 were analyzed retrospectively. Patients were given 256-slice MSCT examinations, including whole brain CTP and CTA. The cerebral perfusion parameters [cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP)] in the infarct areas and contralateral mirror imaging areas were compared, and the head and neck artery stenosis and occlusion were recorded. Results CTP examination showed that 48 patients had cerebral perfusion abnormal areas which were consistent with clinical symptoms, and the levels of CBF and CBV in infarct areas were lower than those in contralateral mirror imaging areas, and the MTT and TTP were longer than those in contralateral mirror imaging areas (P<0.05). CTA examination found there were 56 vascular lesions among 48 patients, including 11 cases of mild stenosis (19.64%), 21 cases of moderate stenosis (37.50%), 18 cases of severe stenosis (32.14%) and 6 cases of complete occlusion (10.71%). Conclusion 256-slice MSCT of whole brain CTP combined with CTA can accurately determine the cerebral infarction areas and corresponding hemodynamic changes, and determine the location and extent of vascular stenosis, and has high clinical diagnostic value for acute cerebral infarction.