From the Navier-Stokers equations,the integral expressions of the free-surface elevation and the velocity field in ship waves of a moving waterborne body are obtained. Next,Lighthill's two- stage scheme is employed to change the above-mentioned integral expressions to algebraic expressions. Compared with the results obtained when the seawater is idealized to an inviscid fluid,the singularities are dispelled or weakened,and the accuracy of the digit information of ship waves is improved.