The copyright against the game which is successful to a performance, is increasing rapidly. The compute r game is sensitive to a popularity. Game from the hazard which it develops short time, the expense which is cheap, about lower the dispute with a copyright, a reproduction and the ticket paragraph increases with the insufficient back of technical power. It analyzes the quality of the tools comparison it will be able to analyze the source codes from the dissertation which it sees. It analyzed the game source code and against the method which produces the original program and the reproduction degree of reproduction program for it researched. The method which produces a reproduction degree game feature following function shares a module especially. After from each module separating a file in file structure, source pro gram and data structure form, it calculates a similarity measure. It followed in important degree of each function and weight it let and the fixed quantity reproduction degree of full game program it produced.