The first part of this thesis focuses on the general introduction of extradosed bridge, including the historical review, structural analysis and design criterion based on the specifications. The second part analyzes a practical example designed by Taiwan engineers in order to illustrate the fundamental principles and structural behaviors of extradosed bridge. In this part, a statically structural analysis is completed to show the differences of design flow chart among the continuous beam bridge, cable-stayed bridge and extradosed bridge. Finally, a discussion and suggestion is presented based on the results of the previous analysis. A software program TANGO written by Finite Element Method is used in this thesis to do the analysis. The variation of internal forces, displacements and cable forces under various load combinations have been studied. The envelopes of influence lines is drawn to ensure the stress which meets the requirements of design codes.