Unilateral carotid artery ligation which could induce adaptive improvement is a classic model that has been widely used to study pathology of ischemic disease.In those studies,blood flow is an important parameter to characterize the ischemia.Laser Doppler flowmetry is commonly used to measure the blood flow velocity,however,relatively low resolution refrains its application in this domain.Optical coherence tomography(OCT)is a powerful imaging modality which can provide depth resolved images in biological tissue with high spatial and temporal resolution.By calculating phase shift between adjacent two A-lines,Doppler flow distribution can be achieved.These advantages make OCT technology more and more popular on research of small animal model.In this study,blood flow volume was calculated based on the Doppler OCT image and the Doppler angle which is achieved by 3D structural image reconstruction.SPF rats was anesthetized with isoflurane and divided into two groups.The first group,bilateral carotid artery was surgically exposed,and then left carotid artery was ligated.Blood flow changes of the contralateral carotid artery was monitored using high speed spectral domain optical coherence tomography,including the absolute flow velocity and the flow volume.In the other group,skull window was opened at the ipsilateral cerebral cortex of ligation,blood supply of small artery was measured before and after the ligation.The measured results demonstrate the blood supply compensation process after unilateral carotid artery ligation.Our work shows that OCT is an effective technology which has the potential for researches correlated with the model of unilateral carotid artery ligation.