Abstract: To better understand the wave-induced longshore currents in nearshore region, a numerical model is developed based on the second order fully nonlinear Boussinesq equations.The governing equations possess optimum linear properties and second order fully nonlinearity characteristics in medium water depths.The relaxation zone method is used to generate non-reflective and higher-order nonlinear waves, and the periodic lateral boundary conditions are imposed to mimic open sea boundaries.Utilizing the developed model, the effect of involved parameter values on the numerical results are investigated by conducting numerical experiments.Good agreements between numerical results and experimental data demonstrate the accuracy and applicability of the model.The effects of different wave conditions on longshore currents are also investigated numerically.