A 3D numerical wave tank suitable for wave-current interactions was created based on Navier-Stokes equations and continuity equations. The wave diffraction and runup effects were simulated in this numerical wave tank. Different wave-current combinations were selected to investigate the current effect on wave disturbance and trajectory of water particles. In order to verify the accuracy of the numerical calculation, a model test on wave run-up in wave alone condition near column wall was conducted. The results show that the values of calculation and model test are in good agreement.