A simplified model for free vibration analysis of functionally graded plates is proposed based on higher-order shear defor? mation theory， the most significant feature of which is that it applies for the vibration analysis of functionally graded plates without any shear corrections. Compared with other shear deformation theories that contain more unknown variables， this model contains only one control equation， and thus greatly reduces the computational cost. Based on this simplified model， the free vibration of functionally graded rectangular plates with simple support boundary conditions is investigated and compared with other existing lit? erature. The results show that the simplified model proposed in this paper is simple and accurate in solving the free vibration behav? ior of functional gradient plates. In addition， the effects of different gradient indices， aspect ratios， and length-thickness ratios on the free vibration behavior of functionally gradient plates are analytically discussed in the paper by several numerical arithmetic ex? amples.