An investigation on nonlinear dynamics of panel with boundary condition relaxation is carried out in this paper. The flutter differential equations of a three-dimension panel are set up by using separation of variables and Galerkin method. The first piston theory is employed to calculate the aerodynamic load on the panel. At first, the flutter boundary and stability for the flat pane are analyzed. Then Using the temperature, dynamic pressure and in-plane load as bifurcation parameters, their bifurcations and chaos behaviors were studied. The results demonstrate the rich dynamic behaviors of the panel with boundary condition relaxation and complex dynamic characteristic with variation of bifurcation parameters. Both the buckled region and chaotic region increase as the relaxation of boundary conditions and the stability of system decreases.