Objective To study the asymmetry of velocity profile under steady flow condition in the curved common carotid artery(CCA) in vitro.Methods The PIV is used to measure velocity profiles on vertical and horizontal planes of CCA in different localities under physiological average,peak and limited Reynolds numbers of CCA models of 1:20 and 1:60 curvatures.Result The skewed parabolic profile is observed in CCA under 1:60 curvature and physiological average Reynolds number.As curvature and Reynolds number increase,the middle of horizontal profile appears sunken and the vertical profile is M-shaped.There are different profile shapes in different localities along the curved pipe.Conclusion The experimental data were provided for the asymmetric inlet velocity profile condition of carotid bifurcation,and for understanding the changes of velocity profiles shapes along with Reynolds numbers,curvature and localities of the curved pipe.