In the game development differently with general software development, game planers, programers, and graphic designers, the specialists of the various fields, accomplished one team and they are advanced all to their goal. So it is very difficult for the development participants to communicate each other accurately and efficiently. For successful game development, all development participants should understand accurately the contents of the game design document. Specially the game mechanics as a major part of game design, requires the no-error contents, the no-error expression, and the no-error readings to all development participants because it contains almost game-play logic. It becomes more difficult for the development participants to understand accurately the game mechanics which becomes larger and complicated as the size of game development becomes larger. And configuration management of the game mechanics becomes more complicated and inefficient. In this paper, we propose a new representation method of game mechanics using UML notations for solving this problem. The proposed method satisfies the visual expression and the logical expression simultaneous for the requirements of the game mechanics because of UML notations. And the proposed method could be an efficient management of configuration because the management is based on the UML model management. The proposed representation of game mechanics of "Capture The Dude" game, shows good visual expression and good logical expression.