In this paper, Bi2O3 doped with different amount of La3+ was prepared. The prepared photocatalysts were characterized by BET, XRD, UV-VIS diffuse reflectance and XPS. The results show that 3%La3+-Bi2O3 prepared has the highest BET surface area, pore volume, the smallest pore size. 3%La3+-Bi2O3 exhibits the best photocatalytic activity. The results of further experiments show that the specific surface area, UV-Vis diffuse reflectance and the binding energy all play an important role in promotion of photocatalytic activity of Bi2O3 nanostructure.