Abstract: Based on the rigidity plate and the small deflection theories, and considering the physical nonlinearity of concrete, the equilibrium and stability equations of reinforced concrete rectangular plate subjected to thermal loading are derived. The close-form solutions of the critical buckling temperature difference for a simply supported RC rectangular plate under temperature variation perpendicular to surface and uniform temperature change are presented, and the critical buckling temperature variations of frequently used reinforced concrete rectangular plates with simply supported boundary conditions in engineering are calculated, and the influences of material parameters, length-breadth ratio and relative thickness on the critical buckling temperature difference are discussed, which provides a basis for the calculation of the critical buckling temperature difference for reinforced concrete rectangular plates.