TiO2 was prepared by sol-gel method using tetrabutyl titanate as precursor. TiO2 was loaded on Bi12TiO20. The photocatalyst with different TiO2 loading was calcined at 723 K. The photocatalytic activity of decomposition gaseous benzene was investigated in a batch reactor. The prepared photocatalyst was characterized by UV-vis diffuse reflectance. The result showed that TiO2/Bi12TiO20 absorbed much more ultraviolet light than TiO2 in the ultraviolet light region and showed red shift. The results indicated that the prepared photocatalyst can greatly promote the photocatalytic activity. The 2.0% TiO2/Bi12TiO20 system exhibited the highest photocatalytic activity.