The invention discloses a plate structure dynamic characteristic analysis method considering pre-deformation under thermal environment. The method includes such steps as calculating linear stiffness matrix, thermal stress stiffness matrix and nonlinear stiffness matrix considering pre-deformation according to structural material parameters under initial force load and thermal load, integrating linear stiffness matrix, thermal stress stiffness matrix and nonlinear stiffness matrix into total stiffness matrix; the dynamic equation of plate structure considering pre-deformation in thermal environment being established, and the governing equation of generalized eigenvalue problem being established according to the dynamic equation of plate structure; then the dynamic characteristics of plate structure considering pre-deformation in thermal environment being obtained by modal analysis. The dynamic characteristic analysis method of the invention comprehensively considers the geometrical nonlinearity caused by the pre-deformation and the influence of the thermal environment on the structural stiffness, so that the method can be applied to the structural dynamic characteristic analysis under the complex load environment. The invention can effectively improve the analysis precision of the dynamic characteristic of the plate structure under the complex environment, and guide the engineering structure design.