Abstract: Regional bus scheduling,treated as a “part of trips completed by a vehicle”set-partitioning problem,ould be formulated as a multi-objective mixed integer programming model,where some side constraints such as depots capacities,fuelling and the latest time of going back to depot were considered.The previous objective was to maximize vehicle utilization for all buses,and the secondary objective was to maximize reliability of scheduling plans.Before the model's non-inferior solutions were obtained by genetic algorithm,it was converted into a single objective programming problem with constraint method.Finally,an example shows that the high reliability of schemes become,the less vehicle utilization will get.