Abstract: The study on nucleation of molecular-Sieve-Zeolite is an important key to the investigation of the mechanism of formation and crystal growth of Molecular-Sieve-Zeolite. This is one of the problems to which Zeolite-Chemists pay close attention. But there is no efficient method so far. We applied broad line Na²³-NMR technique to investigate the existence and growth of nucleation center with Faujasite type structure in a colloidal system and obtained some satisfactory results if sizes of the nuclei were bigger. To look for new research means, we made use of electron diffraction method to detect and study the nuclei in a sol of aluminosilicates. An example was introduced here. It is proved that there are nuclei of NaX type Zeolites in a sol of Faujasite type "Directing-Agent" which ages in a short time. So the application of the electron diffraction method to investigate the nucleation of Zeolite in a liquid phase seems to be a new development.