The problem of timetabling system is the typical of combinatorial optimization and uncertainty, and it also is NP-completeness problem. With the development of colleges and universities,the class arrangement model is also becoming more and more complicated in the educational administration system. In view of this situation, the paper presented the mathematical model of the problem, and proposed solutions to apply genetic algorithm based on C sharp. The results show that the algorithm can solve the timetabling problem effectively. This method is easy to learn and apply. And it does not need any special realization model.