Objective To study the effect of carotid artery stenting (CAS) on rCBF and rCVR.Methods Seventeen patients with unilateral internal carotid artery symptomatic severe stenosis who underwent CAS in our hospital were included in this study.Their rCBF volume and rCVR were measured by single photon emission CT scanning combined with CO2 loading test 1 week be fore and 3 months after CAS.Their data were analyzed according to the ROI in ipsilateral middle cerebral artery blood supply territory.Results Sixty eight ROIs were detected in the 17 patients with impaired rCBF in 16 ROIs (23.5％) before CAS.The mean improved rate of rCBF was significantly higher in impaired rCBF and rCVR ROI before CAS than that of rCBF in normal and impaired rCVR ROI after CAS (P=0.001).The mean improved rate of rCVR was significantly higher in normal rCBF and impaired rCVR ROI after CAS than before CAS (P=0.014).The improved rate of rCBF was significantly higher in impaired rCBF and rCVR ROI after CAS than that of normal and impaired rCVR ROI before CAS (81.3％ vs 50.0％,P=0.027).The improved rate of rCVR was significantly higher in normal rCBF ROI and impaired rCVR ROI before CAS than in impaired rCBF and rCVR ROI after CAS (59.6％ vs 31.3％,P=0.047).Conclusion CAS can improve the ROI rCBF and rCVR in patients with unilateral ICA symptomatic severe stenosis.Its modified model is closely related with rCBF before CAS.