Abstract: The changes in concentrations of the components SiO₂ and Al₃O₃ and in weight average molecular weight (Mw) of SiO₂ as a function of the crystallization time in the liquid phase of gel were investigated by using chemical analysis and low angle laser light scattering methods respectively. Results have shown that the formation of NaYtype zeolite follows the liquid phase mechanism. The existence of the microcrystal of NaY type zeolite in the liquid phase of gel in the course of the crystallization of NaYtype zeolite was proved by the experiment of electron diffraction.By means of determining by X-ray powder diffraction the silica-alumina ratio and its change of NaYtype zeolite presented in the crystal phase at the intervals of crystallization time, it has been found that the silica-alumina ratio of the NaYtype zeolite formed in the course of crystallization decreases gradually with the rucleation and crystal growth of NaYtype zeolite, which show the heterogeneity of the composition silica-alumina ratio of the NaYtype zeolite formed in the course of crystallization.