Biomechanical assessment of atherosclerosis has been mainly studied by tissue characterization and elasticity measurement of arterial wall in biomedical ultrasound. On the other hand, fluid shear stress on the artery is also known as an important factor to change vascular endothelium properties leading to atherosclerosis. Ultrasound is a suitable imaging modality to measure blood flow with high temporal resolution. However, conventional Doppler method merely measures the velocity component along the ultrasonic beam. In the present study, two-dimensional blood flow vectors in carotid artery are measured by dual-angle Doppler measurement and validation of the method is performed in comparison with particle image velocimetry. Further, wall shear stress is calculated by flow distribution in the carotid artery. The study contributes to understand the pathophysiology of atherosclerosis in a non-invasive manner.