La-doped Bi2O3 were prepared via a simple sol-gel method following a facile low temperature calcination process, and citric acid as an organic complexing agent. La3+ doping could not only create oxygen vacanices (OVs) on the surface of Bi2O3, but also as the efficient scavenger to capture photogenerated electrons. The novel x% La-Bi2O3 photocatalysts exhibited oxidation capacities for degrading azo dye methyl orange (MO) and colorless pollutant phenol, and 2% La-Bi2O3 sample showed the highest photocatalytic activity. The enhanced photocatalytic activity in MO and phenol photo-degradation were attributed to the strong synergistic effects of La3+-doping and oxygen vacancies (OVs), which La3+ ions capture, transfer, and release the photo-generated electrons for conversion from O-2 to .O2- to prevent the hot e(-) of CB to jump into the level of OVs, thereby increase separation efficiencies of photo-generated electrons and holes. The present study may present a new perspective for the utilization of rare earth ion doping to improve the performance of other photocatalytic materials.