Objective To discuss the application of lowdose brain CT perfusion imaging of patients with ischemic strokes.Methods The brain CT perfusion imaging and the clinical data of 218 patients were analyzed, which were diagnosed clinically as acute ischemic stroke in the emergency department of West China Hospital of Sichuan University from Sep.2015 to Jul.2016. The clinical diagnostic value was discussed based on the Guidelines for the Diagnosis and Treatment of Acute Ischemic Stroke in China 2014. The ipsilateral and contralateral CTP parameters of patients with ischemic cerebral apoplexy were analyzed including CBF, CBV, MTT and TTP. The semidark band and contralateral CTP parameters were also analyzed.Results The sensitivity and specificity of low dose CT perfusion imaging were 87.3% and 75.6% respectively（P＞0.05）, and MTT was the most sensitivity. There were statistically differences of the ipsilateral and contralateral CTP parameters of patients with ischemic cerebral apoplexy including CBF, CBV, MTT and TTP (P＜0.05). There were statistically differences of the semidark band and contralateral CTP parameters of patients with ischemic cerebral apoplexy including CBF, MTT and TTP (P＜0.05).Conclusion Low dose brain CT perfusion imaging could have higher diagnostic value based on clinical criterion, and could provide reliable evidence for doctors.