Abstract: University exam timetabling problem belongs to optimization problem based on many constraints.The caculation of tradional genetic algorithm reached to index-size and the operation maybe break the hard constraints and can not find an ideal or feasible solution.This paper optimizes initial solution which satisfies hard constraints and concludes from relationship color algorithm by grouping genetic algorithm from practical applications.Maximize students’ study time under fixed examination week，cut down the caculation and don’t break the hard constraints.