Traditionally, time definite carriers only offer a 2-day regular ground service to shippers in Taiwan. As the result of a gradual increase of demand for and a higher investment return on the express services, more and more time definite carriers enter the same day express services market. However, service characteristics and time commitment for regular and express ground services are quite different. Therefore, carriers typically design a separate and distinguished delivery network for each of the two services. For a set of express service centers, the gruond express service network design problem is to simultaneously design a hub-and -spoke network and determine vehicle routes so that the total operating cost is minimized while meeting the operational and organizational constraints. We construct a bi-level mathematical model and also develop a heuristic algorithm based on the bi-level structure of the problem. We use one of the top three time definite carriers in Taiwan for performance testing. We compare our solutions against the global optimum in a small scale network, and also against the carrier's current operations in its large scale network. Our computational results are encoruaging and show the potential of applying this approach to design carrier's logistical express system.