Abstract: In this paper, the different influence of Lanthanum and Cerium cation on the stability of Y zeolite was studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), multinuclear (27Al, 29Si) solid-state nuclear magnetic resonance spectroscopy (NMR). It was found that although the stabilization of Y zeolite could be enhanced by the introduction of Lanthanum or Cerium cation, the former was more remarkable than the later. These results were also confirmed theoretically by density functional calculations. There was a strong interaction between rare earth species and Y zeolite clusters, which restrained the formation of extra-framework alumina and enhanced evidently the stability of Y zeolite. Furthermore, the interaction between Lanthanum species and Y zeolite was stronger.