SiO2/TiO2 photocatalyst was prepared by a sol-gel method applying tetrabutyl titanate as the precursor and cullets as the carrier. The optimal preparing conditions of the SiO2/TiO2 composite photocatalyst were optimized. The optimal conditions included 2:1 of the molar ratio of tetraethyl orthosilicate to tetrabutyl titanate, 3 load times, 600°C of calcinations temperature, 3 h of calcination time, 3 mL of the dosage of CH3COOH and 5:1 of the molar ratio of water to tetrabutyl titanate. The photodegradation percentage of methylene blue could reach 92.26% under the above optimal conditions. Moreover, after three times of the repeated use, the SiO2/TiO2 composite photocatalyst still had a relatively high catalytic activity and stability, and the recycle percentage of the photocatalyst could reach 92.80%.