Abstract： DTMB5415 was studied without considering free surface effect, the viscous flow fields of ship at different scales including full scale were solved numerically in RANS method and SST kω turbulence model, and the scale effect of axial wake was analyzed in detail. It shows that the reciprocal of mean axial wake fraction of propeller disc exhibits a near linear dependence on Reynolds number in logarithmic scale. For the twin screw warship with transverse stern, only one wake peak exits. The amplitude of axial wake peak decreases with the increase of Reynolds number and the corresponding phase angle shifts at the same time. In the inner area of propeller disk, the amplitude of axial wake peak remains constant when the Reynolds number reaches a critical value. However, in the outer area, the amplitude of axial wake peak becomes smaller when the Reynolds number increases, and reveals nearly a cubic polynomial function dependence on the Reynolds number in the logarithmic scales. The reciprocal of mean axial wake at each radius reveals a nearly linear dependence on the Reynolds number in the logarithmic scales.