Abstract: A nonlinear analytical model is formulated for the dynamic behavior of a simply supported steel box girder with curved prestressed tendons. The equation of motion for this steel box girder is rigorously derived using the variational principal of virtual work. A finite element model, based on the experimental model of the large-scale steel box girder with curved prestressed tendons, is established with ANSYS finite element analysis software. The accuracy of the proposed analysis is verified by the comparison between the result of dynamic testing on a large-scale steel box girder and that of finite element analysis. This paper presents the influence of the magnitude of prestress force，eccentricity of anchor on natural frequency of simply supported steel box girder with prestressed tendons.