Leucite-based glass ceramics have gained considerable attention in dental applications due to their optical similarity to natural dental tissues and their favorable mechanical properties. In this study, the influence of alumina content on the microstructure and physical, chemical, and mechanical properties of leucite glass ceramics was investigated. Starting materials containing 18 to 26 wt.% aluminum hydroxides along with other compounds such as silica, sodium carbonate, potassium carbonate, and lithium carbonate after homogenization were melted and quenched to form glass frits. Heat treatment and sintering at different temperatures (700-1000C) were performed on compacted samples of glass ferrite. The thermal analysis, phase composition and microstructure were evaluated by DTA, XRD, and SEM techniques respectively. Physical and mechanical properties were characterized by measuring of relative density, Vickers hardness, and flexural strength. The results indicated that the optimal temperatures of heat treatment for samples with 18% and 22–26% aluminum hydroxide were 950°C and 1000°C, respectively. Increasing alumina content give a higher viscosity for molten glass on the one hand and a delayed crystallization and lower sinterability for glass ferrite sample on the other hand. For this reason, by increasing of alumina higher than the stoichiometric amount, a decrease in microstructural homogeneity, relative density, and mechanical properties was observed.