It’s an urgent problem to improve the strength of Li2OAl2O3SiO2 glass ceramics by glass composition design and crystallization process control. In this paper, Li2OAl2O3SiO2 glass with specific composition was prepared by meltquenching method, and high strength semitranslucent glass ceramics were prepared by twostep heat treatment. Differential scanning thermal analysis shows that the glass transition temperature is 532 ℃ and there are multiple crystallization peaks. After heat treatment, Xray diffraction patterns prove that Li2Si2O5, LiAlSi3O8, LiAlSi4O10 as the main crystal phases are precipitated in the glass, petalite crystals gradually changes into spodumene crystal phases with the increase of heat treatment temperatures or durations, and average crystal sizes grow from 70 nm (heat treatment parameters: 750 ℃，0.5 h and 780 ℃， 10 h) to 340 nm (heat treatment parameters: 820 ℃， 0.5 h and 850 ℃， 4 h). The glass ceramics change from translucent to opacities. Glass ceramics have excellent mechanical properties, the maximum Vickers hardness is 9.15 GPa, the maximum ringonring load can reach 1 335 N, and the maximum simulated whole machine drop height can reach 162 cm. The glass ceramics can be used as backplane protection glass for mobile phone devices.