Abstract: The finite element motion equation of plate is deduced,the stiffness and mass matrixes with consideration of the moment of inertia areconstructed and the first several natural frequencies are calculated by usingthe sub-space iteration method. The vibration property of generalizedconforming thick/thin element ATF-PQ4a is studied. The influence ofmoment of inertia and shearing distortion on the natural frequencies arediscussed. The results obtained by using this element agree wellwith those obtained by ABAQUS and the theoretical solution. It can beconcluded that the element ATF-PQ4a can be used for both thick and thinplates in the dynamics range for engineering purposes.