This paper presents a theoretical investigation of the frictional resistance of ship by three dimensional boundary layer theory. The stream lines and pressure distributions are found from the linearized potential theory. The momentum equation of the three dimensional turbulent boundary layer used by streamline coodinate and entrainment equation introduced by Cumpsty-Head are integrated numerically along the stream line to determine the momentum thickness, shape parameter and the angle of boundary layer flow to the outer flow. The results of computation for Inuid S-401 and tanker ship form are presented. And the results are compared with the approximate calculation by two-dimensional boundary layer theory.