With the help of a bi-level programming model,the relationship between regional bus scheduling and its procurement scheme is explored from the viewpoint of system theory. According to proposed model’s characteristics,the above issue is equivalently converted into how to assign vehicles to cover all trips to maximize their utilization and determine the vehicle type to minimize the purchase expenses under different numbers of vehicles,where side constraints such as the depot capacity,the fuelling, the emission of polluting gases,etc.,are taken into consideration. The corresponding solutions of upper and lower model to different numbers of vehicles are obtained by using genetic algorithm and the optimal solution is selected by comparing all feasible schemes. Finally,the correctness and effectiveness of the proposed model and the algorithm are verified by an example.