In the study the characteristics change of crystallized $Li_2O$.$Al_2O_3$.$SiO_2$ glass-ceramics when varying RO ratio and increasing Al2O3 were investigated to produce a glass-ceramics with high mechanical strength and low thermal expansion. Parent glass was obtained by melting at 1,350~1,40$0^{circ}C$ for 3 hours and annealing at 45$0^{circ}C$ and the various physical characteristics were measured. Results were as follows; 1. When ZnO was replaced by MgO thermal expansion coefficient was lowered when increasing ZnO content. 2. Major crystal phase was $eta$-spodumene the crystal growth mophology was the three dimensional sphere and the activation energy for crystallization was 54.6 Kcal/mol. 3. Parent glass heat-treated at 95$0^{circ}C$ for 10 hours had ; a) thermal expansion coeff. of $23.2{ imes}10^{-7}$/$^{circ}C$ b)whiteness of 76 c) microhardness of 1,089kg/$mm^2$