Objective In order to provide the basic theory for reasonable management of cerebral perfusion and avoid cerebral ischemia, this study was designed to establish one unique piglet extracorporeal circulation model and explore real-time monitoring of the dynamic changes in cerebral perfusion and regional cerebral oxygen saturation (rSO2) during different stagesof cardiopulmonary bypass (CPB) . Methods Twelve piglets were divided into 3 groups randomly (n = 4) :control group, high blood flow group (H group) and low blood flow group (L group) . A unique double arterial line with single pump was established in this piglet's model. Cerebral flow rates were monitored using TS410 transit-time tubing flowmeters (Transonic Systems Inc., Ithaca, NY) . Regional cerebral oxygen saturation (rSO2) was monitored simultaneously as one of parameters of cerebral autoregulation. Arterial samples were drawn to measure the concentrations of S100 protein. Hematoxylin-eosin (HE) and Nissl staining were performed to detect morphologic characteristics of hippocampus. Results During cross-clamping of CPB, cerebral blood flow in L group [ (19. 0 ± 7. 4) mL/ (kg·min) ] was lower than that in H group [ (30. 8 ± 9. 9) mL/ (kg · min) ] (P = 0. 072) , and the rSO2 in L group (47. 3% ± 3. 3%) was lower than that in H group (52. 6% ± 3. 1%) (P<0. 05) . There were no significant difference in HE and Nissl staining in hippocampus neuron among the three groups. Conclusions The current study demonstrated that the impairment of cerebral autoregulation and cerebral perfusion was determined by the whole blood flow of extracorporeal circulation. High blood flow in extracorporeal circulation had better cerebral perfusion during cross-clamping than low blood flow.