The velocity of underwater bullets decrease quickly because of the surface friction. How to reduce drag and increase its shooting distance, or how to keep its kinetic energy and execution in regulating shooting distance, this should be considered in designing a new water project. In the paper, several kinds drag reduction methods are introduced, the riblets surface is used in designing bullets. It's compared the influence of micro-groove surface with normal bullets as water bullets flying at high speed though experiment, and the phenomenon is explained by supercavitation theory.