Abstract:Through the finite element analysis program ANSYS, three-dimensional finite element models for two pylons cable-stayed bridges are set up, and the influence of the structural parameter,the ratio between height of tower and length of main span, on the dynamic characteristics of two pylons cable-stayed bridges is studied in the paper. The analysis draws the general conclusions on the parametric sensitivity about dynamic characteristics of two pylons cable-stayed bridges. These conclusions are propitious to the modification of finite element models, and also, provide some gist to the concept design and the constitution design.