The current study presents a new analytical method for buckling analysis of circular plates with constant thickness and Poisson’s ratio, made of functionally graded material subjected to radial load. Governing equations are based on energy method for thin plates. The boundary conditions of the plate are assumed to be simply supported and clamped. The stability equations were obtained by using conservation of energy. The critical buckling load and first mode shape in terms of Bessel function of the first kind were obtained using Variational Calculus method. Increase in buckling capacity and improvement in the behavior of functionally graded plates in comparison to homogenous plates have been investigated