The dynamic behavior of simple supported rectangular thin plate subjected to transverse harmonic excitation is investigated in this paper. The compressive loads N1 andN 2 is applied on edges of the plate. On assumption of small deformation, dynamic governing equation is derived. The constitutive relation of material obeys can be stood foran integral equation. By use of nonlinear Galerkin method, the partial differential governingequation is turned into integral-differential variation of the buffing equation. The different kinds of behaviors are investigated making use of the classical tools of nonlinear dynamics, such as the phase portrait, the time-displacement history and Lyapunov exponent analysis. The results of analysis show that the values of N 1 and N2，character time of materialhave large influence on the dynamic response. When they satisfy some condition, chaotic motions may occur in the dynamic system.