Abstract: An analytical model for analyzing the buckling characteristics of full composite grid/corrugated sandwich panels was provided. Regarding the corrugation and the grid core as a continuous single layer, the internal force-strain relationship of the full composite corrugated/grid sandwich panel was derived based on the refined plate theory. On the basis of considering the anisotropy and transverse shear deformation of the composite core panel, the equivalent elastic constants of composite orthogonal grid and trapezoidal corrugations cores were deduced based on the homogenization theory. Using the minimum potential energy principle, the buckling balance differential equation of full composite grid/corrugated sandwich panels was obtained, and the critical buckling load under three boundary conditions was transformed. The analytical results were compared with the finite element simulation and the errors are within 5%, which validates the correctness and effectiveness of the analytical model. The verified model was used to compare and analyze the effect of the layers angle, number of layers as well as the height of core, inclination angle of corrugation and grid spacing on the critical buckling load and the specific critical buckling load of the full composite grid/corrugated sandwich pane, which provides theoretical guidance for the buckling characteristic analysis and optimal design of this type of structure.