The preparation of block glass with characteristics such as strong white emission photoluminescence, high stability, and low toxicity is of great significance to the progress of LED display technology. In this study, we prepared Al₂O₃-xSiO₂ block xerogels of different components using the sol-gel method. During sintering at about 500 ℃, the glass exhibits a strong white visible photoluminescence wide peak due to the radical carbonyl-terminations defects from the pore surface, and the luminous intensity is obviously related with the concentration and luminous intensity of radical defects.