It is a viable form of drag reduction for airship to use airship envelope with micron-scale grooves. In this paper, the k-ω SST turbulence model is used to analyze the V-shaped micro-riblets. The velocity and pressure field are obtained using this model. Both the drag reduction mechanism for micro-grooves and the influence of different groove size are analyzed by the streamline pattern and the drag reduction rate. The results show that the streamline pattern is an important reason for drag reduction ability, and the grooves with appropriate size can reduce the drag between fluid and wall.