Large deployable parabolic antenna has attracted great attention due to its special value. Radial stiffening ribmembrane umbrella antenna in this article is a typical nonlinear structural system. Establishing the FE model of the radial stiffening ribmembrane umbrella antenna rationally and accurately is very important to study its onorbit dynamics characteristic. The temperature pretension equivalent method is employed to settle the initial condition and describe the pretension in the physical model of the radial stiffening ribmembrane umbrella antenna .The dynamics characteristic is obtained by FEM calculation, which provides essential data for structure design and mechanical research for the radial stiffening ribmembrane umbrella antenna.