Objective To investigate the application of whole-brain CT perfusion imaging in patients in early stage of severe traumatic brain injury.Methods A total of 106 patients with severe traumatic brain injury caused by trauma who were treated in our hospital were enrolled as observation group， and 60 patients with mild brain trauma were enrolled as control group. All patients underwent 256-slice whole-brain CT perfusion imaging within 24 hours after injury， and the two groups were compared in terms of cerebral blood flow （CBF）， cerebral blood volume （CBV）， mean transit time （MTT）， and prognosis after 3 months.Results Compared with the control group， the observation group had significantly lower CBF values of the basilar ganglia， brainstem， frontal lobe， and parietal lobe and a significantly higher MTT within 24 hours after injury （all P <0.05）. The CBF values of the basilar ganglia， brainstem， frontal lobe， and parietal lobe were positively correlated with Glasgow Outcome Scale （GOS） score （r_s = 0.902， 0.891， 0.859， and 0.786）. CBV of the thalamus was associated with GOS score.Conclusion Reduction in CBF and prolongation of MTT are observed in patients in early stage of severe traumatic brain injury， and CBF value is positively correlated with prognosis. Whole-brain CT perfusion imaging has a certain clinical value in predicting the prognosis of patients with severe traumatic brain injury in the early stage.