The mechanism of stabilization of rare earth ions on Y-type zeolite was further studied and discussed beginning with the hydrothermal stability of REY (modified Y zeolite by different rare earth ions), and through combining the change of microenvironment and corresponding macrocharacteristics by means of X-ray powder diffraction (XRD) in conjunction with Rietveld structural refinement, X-ray fluorescence spectrometry (XRF), Fourier transform infrared spectroscopy (FT-IR), nitrogen physico-adsorption and desorption techniques, and microreaction activity evaluation (MAT). The results show that the matching degree between the framework environment of zeolite and the characteristics of rare earth ions is particularly important for improving the hydrothermal stability of REY. The protection of structural unit integrity by the multicore rare earth bridging structure involving more nonskeleton oxygen atoms is the root cause. In addition to acidity, a closer correlation between hydrothermal stability and FCC (fluid catalytic cracking) catalytic activity of REY zeolite deserves more attention.