Abstract: Through analysis the characteristics of turbulence simulation methods at present and the actual requirements in drag reduction investigations over riblets surface,the simulation method of riblets surface flow field based on Reynolds-averaged N-S equation has been established.In allusion to the different characteristics of the longitudinal and transverse riblets surfaces,different computational regions and computational meshs were selected reasonably.A series of simulation results gain in this paper prove that not only the drag reduction values but also the distributing characteristics of flow velocity,pressure,and vortex,etc over riblets surface could be gain accurately using the computational methods.