Abstract: Based on the small deflection theory of plate,the physical nonlinearity of concrete were taken into consideration,and the equilibrium and stability equations of rectangular reinforced concrete plate subjected to thermal loading condition on elastic subgrade were derived.The closed form solution of the critical buckling temperature for a simply supported rectangular plate made of reinforced concrete under uniform heat variation were presented,and the influences of material constant,length-breadth ratio,relative thickness and bedding coefficient on the variation of buckling temperature were discussed.And so the theoretical basis of calculation for the critical buckling temperature of reinforced concrete rectangular plates on elastic subgrade in engineering structures was provided.