With the expansion of urban scale, traditional public transit struggles to fulfill long-distance travel demands (Rail transit is costly and fixed-route transit is time-consuming). This paper proposes a bimodal transit system with point-to-point transit (PPT) services and fixed-route transit (FRT) services. PPT is designed for passengers traveling long distances, efficiently linking two major transport hubs with few intermediate stops. We formulate the joint design problem as a mixed-integer program through a parsimonious continuum model. By minimizing the system cost, the sum of agency and user costs, we determine optimal design parameters using MATLAB built-in genetic algorithm. Through numerical experiments, we analyze how the performance of the bimodal transit system varies with demand, city size, and other factors. Our results demonstrate that the proposed system is more cost-efficient than the regular system in cities with high travel demand. The proposed model can be used for the sketchy design of such bimodal transit system and provide a theoretical foundation for the adjustment of public transit networks.