Objective To explore the value of four-dimensional CT angiography combined with whole brain CT perfusion imaging in the diagnosis of ischemic stroke. Methods The whole brain CT perfusion imaging and conventional head CTA examination were performed in 42 patients with ischemic stroke. Meanwhile the whole brain plain images and 4D-CTA images were also generated from volumetric data acquired in the whole brain CTP. Images quality, vascular stenosis degree and CTP parameters were analyzed. Results The image quality ratings for 4D-CTA and the conventional CTA are (2.67±0.48) and (2.81±0.39) respectively. 4D-CTA and conventional CTA diagnosis of cerebral artery stenosis were not significantly different (P>0.05), and there was definite consistency. 4D-CTA found that the cerebral artery of 7 cases were normal, 35 cases had different degrees of stenosis or occlusion. 4D-CTA showed more collateral circulation than conventional CTA in 2 cases, moreover, the rate of collateral circulation in patients with severe stenosis and occlusion was significantly higher than that in patients with mild or moderate stenosis. CT perfusion imaging was positive in 34 patients and negative in 8 patients. The CTA vasoconstriction patients demonstrated a striking higher CTP positive rate compared with the ones without hemadostenosis. Conclusion 4D-CTA combined with CTP can not only monitor the cerebral hemodynamics conditions, but can also clearly demonstrate the changes of cerebral artery, which can replace the conventional CTA examination, and provide more comprehensive information for clinical treatment.