Abstract: Zeolite A was synthesized by hydrothermal crystallization using the acid-treated stellerite as raw material. The synthesizing process was examined by XRD and SEM. In this reaction process, the SiO₂ and Al₂O₃ in solid phase were translated into the SiO₂ and Al₂O₃ in the liquid phase continuously, when the acid-treated stellerite and NaAlO₂ were dissolved. These phenomena indicate that the formation mechanism of zeolite A is the solution-mediated transport mechanism, because the formation of zeolite A is drived by the concentration supersaturation of the composition in liquid phase, and is transported by solution-media.