For I-girder with high strength steel, it is known that the flexural ductility is considerably decreased by increasing the yield strength of material. Thus, it is necessary to conduct a study for guaranteeing proper flexural ductility of I-girder with high-strength steel. In this study, the evaluation of flexural ductility of negative moment region of I-girder with high strength steel where yield stress of steel is 690Mpa is presented based on the results of finite element analysis and experiment. From the results, it is found that the flexural ductility of the I-girder is significantly reduced due to the increase of elastic deformation and the decrease of plastic deformation ability of the material when the yield strength increases. This study proposed equation predicted flexural ductility of high strength steel in negative moment region. It is also proposed the method to improve the flexural ductility by an unequal installation of cross beam and an optimal position of cross beam. Finally, the effects of the unequal installation of cross beam on the flexural ductility are discussed based on the finite element results and the experimental results.