A NaY molecular sieve with an aluminum-rich surface is prepared using a process that includes the steps of: a. mixing a directing agent and a first silicon source to obtain a first mixture, wherein the directing agent has a molar composition of Na2O:Al2O3:SiO2:H2O=(6-25):1:(6-25):(200-400); b. mixing the first mixture obtained in the step a with a second silicon source, an aluminum source and water to obtain a second mixture; c. carrying out hydrothermal crystallization on the second mixture obtained in the step b, and collecting a solid product. Calculated as SiO2, the weight ratio of the first silicon source to the second silicon source is 1:(0.01-12). The NaY molecular sieve has larger aluminum distribution gradient from the surface to the center of the particle than the conventional molecular sieve.