Abstract: Objective To explore the application value of routine CT and perfusion CT in evaluating the prognosis of ischemic stroke in recovery period, and to clarify the application advantage of low dose perfusion CT. Methods A total of 80 patients in the recovery period of ischemic stroke diagnosed and treated in our hospital from May 2018 to May 2019 were included in the study by retrospective analysis. All patients underwent routine CT scan and perfusion CT scan. At the same time, according to different doses of perfusion scan, they were divided into routine dose group and low-dose group with 40 cases in each group. The results of the two groups were compared, and the prognosis evaluation of low-dose perfusion CT was analyzed. Results The old infarcts were detected by regular CT scan in 80 patients. The old infarcts were detected by perfusion CT in 57 patients, including 28 by conventional dose perfusion CT and 29 by low dose perfusion CT. There was no significant difference between the two groups in the detection of cerebral blood flow, cerebral blood volume, mean transit time and local perfusion peak time in infarct center and ischemic area(all P>0.05). Under low dose perfusion CT examination, the detection values of cerebral blood flow and cerebral blood volume in ischemic area[(0.79±0.30) mL/(min·g),(0.93±0.22) mL/g] were higher than those in infarct center area[(0.22±0.19) mL/(min·g),(0.27±0.13) mL/g], and the detection values of mean transit time and local perfusion peak time[(12.7±3.1) s,(22.1±4.0) s] were lower than those in infarct center area[(18.8±3.9) s,(24.4±3.7) s], with statistical difference significance(t=10.152, 16.335, 7.744, 2.670, all P<0.05). The radiation dose of low dose group[(1.50±0.27) mSv] was significantly lower than that of conventional dose group[(3.48±0.61) mSv], with the significant difference(t=18.772, P<0.001). Conclusion The perfusion CT is helpful to evaluate the prognosis of patients in the recovery period of ischemic stroke, and it can accurately evaluate the improvement degree of local blood flow perfusion in the ischemic area, and low dose perfusion CT can reduce the radiation dose, which has an important guiding significance for clinical diagnosis and treatment.