The hydrogen transfer properties of HY zeolite and lanthanum ion modified Y(LaHY) zeolite were investigated using in situ FTIR technology. Combined with characterization data of zeolite crystal structure, texture properties, and acidity, the regulatory mechanism of rare earth modification and hydrothermal treatment on the hydrogen transfer reaction performance of Y zeolite was explored. The results show that the Brønsted (B) acid density and strong acid strength of Y zeolite decreased, while rare earth species located in the supercage formed weak Lewis (L) acid sites. The synergistic effect of B acid and L acid sites in the supercage promoted the occurrence of hydrogen transfer reaction. After hydrothermal treatment, the total acidity of HY-LH and LaHY-LH zeolites significantly decreased, and the L acid centers related to rare earth species in the supercages completely disappeared, which significantly reduced the hydrogen transfer reaction performance of HY zeolites. The research results can provide important theoretical guidance for a deeper understanding of the laws of hydrogen transfer reactions in catalytic cracking reactions, as well as achieving the goals of regulating olefin product selectivity and inhibiting coking deactivation.