Objective To study the clinical value of color Doppler ultrasound in carotid endarterectomy ( CEA) .Methods Forty-five patients with CEA were examined and analyzed by TCD and CDFI.The position, range,character,diameter,stenosis rate were measured by CDFI and collateral flow by TCD before CEA.The intraop-erative CDFI was applied to confirm the flow and the flaps in carotid artery.TCD monitoring of middle cerebral blood flow in CEA to assess whether use shunt technique and cerebral hyper-perfusion.CDFI was applied to assess patency and intimal hyperplasia of carotid artery.Results Seventeen low echo plaques,twelve high echo plaques and sixteen hypoechogenicity echo plaques in forty-five patients with internal carotid stenosis were found by color Doppler ultra-sound.Blood flow volume increased significantly in the ispilateal internal carotid arteries and middle cerebral arteris after operation.Carotid artery restenosis was not found by color Doppler ultrasound after CEA.Conclusion Applica-tion of color Doppler in CEA is valuable in the diagnosis of internal carotid stenosis,intraoperative monitoring and in the evaluation of effect.