Abstract: A method is presented for carrying out nonlinear thermal buckling anlysis of composite laminates,based on a high-order displacement theory andamodified Hahn-Tsai nonlinear constitutive model.The high-order displacement theory takes account for both transverse shear deform ation and transverse normal strain effects.The nonlinear constitutive model includes nonlinearity not only between shear stresses and shear strains but also between transverse normal stresses a.nd strains.A damping parameter approach is used in order to improve the accuracy of solutions.Numerical results show that material nonlinearities significantly affects nonlinear thermal buckling behaviors of composite laminates.