Hydrothermal synthesis of high-silica MOR type zeolite at the temperature range of 413-433K was investigated in amine-free and fluoride-free Na2O-Al2O3-SiO2-H2O reactant system using different alumina source in presence of ether, which plays an effectively promoting role on the crystallization and the increasing the molar ratio of silica to alumina (SAR) for the zeolite. SAR and the alkalinity in the starting reactant gel make essential effects on the crystallization of the zeolite with pure phase. The crystallization phenomena in the reactant prepared with different alumina sources are similar, except obvious differences on the morphology and SAR of the as-synthesized MOR zeolites. Pure phase MOR zeolite with SAR up to 30 was obtained in the reactant with optimum compositions and under a certain reaction condition. Characterized by nitrogen sorption and 27Al magic–angle spinning (MAS) nuclear magnetic resonance (NMR), perfect framework and open channel system of the zeolite has been proved. The high silica MOR zeolite exhibits much more excellent hydrothermal stability in comparison of the low SAR one.