Abstract: The equation of motion of panel flutter is a nonlinear partial differential equation. It is usually treated approximately by a system of ordinary differential equations. In this paper the author makes an infinite dimensional nonlinear analysis for panel flutter; （ 1 ） using the infinite dimensional Hopf bifurcation theory to find the bifurcation values, and （ 2 ） using center manifold theory to determine the stability of the bifurcating periodic motions.