In this study, a viscous-inviscid method based on velocity decomposition is presented. The velocity of the flow field is decomposed into viscous velocity and inviscid velocity, the inviscid velocity is applied for the whole domain, which includes the damping area, and the remaining viscous velocity is just acting on a small domain around the ship hull according to the boundary layer theory. The remaining viscous velocity is computed by a modified N-S equation which coupled the inviscid part, after the inviscid velocity is obtained by solving Euler equation. The simulation of Wigley hull advancing in calm water is accomplished with present method also the decomposed velocity has been studied. The result shows the present method is robust and can be a practical method for partial viscous correction.