Abstract—A flexural experiment was conducted on the tested prestressed concrete girder using carbon fiber reinforced plastics (CFRP) tendons, which has the full scale of an actual one and was placed next to the main girders of Shinmiya Bridge in the corrosive environment nearly 30 years. In this study, the flexural behavior of this tested girder was investigated by the finite element method. A three-dimensional analysis model was built in LS-DYNA and analyzed by an explicit finite element program. The load-bearing capacity, load-deflection curve, and the crack pattern were evaluated in comparing with experimental results. The comparison result showed that there was a consistency between results obtained from the simulation and that obtained from the experiment of the tested girder in 2017. Based on this model, the decrease of pre-stressing force in the tendons, the reduction of the compression concrete strength were studied to evaluate the change in the behavior of the structure.