Abstract: Many laboratory expermients on wave-current interaction have shown that a reduction in the current intensity is achieved when the wave propagate in the direction of the current,while the opposite is true when the current flowing in the opposite direction of the wave propagation.In this study,the expressions for the boundary shear stress and the velocity profile under the influence of wave-current interaction are derived to expla in the laboratory observed phenomena.The expressions are the Navier-Stokes equation based,which use the small am plitude wave theory as sumption and incorporate with the Grant Madsen model for wave-current bottom boundary layer flow.The result shows that our expressions are able to smiulate the in fluence of wave height and viscosity on velocity profiles,and the smiulation coincides with the observation.Also,our expressions are simple and practical com pared to other wave-current models.Using the expressions,an influencing factor analysis is performed on the laboratory observed phenomena,and the result is presented.