Bi‐ and Y‐codoped TiO2 photocatalysts were synthesized through a sol‐gel method, and were applied in the photocatalytic reduction of CO2 to formic acid under the visible light irradiation. The results revealed that, after doping Bi and Y, the surface area of TiO2 was increased from 5.4 to 93.1 m2/g when the mole fractions of doping Bi and Y were 1.0% and 0.5%, respectively, and the lattice structures of the photocatalysts changed and the oxygen vacancies on the surface of the photocatalysts formed, which would act as the electron capture centers and slowing down the recombination of photo‐induced electron and hole. The photocurrent spectra also proved that the photocatalysts had better electronic transmission capacities. The HCOOH yield in CO2 photocatalytic reduction was 747.82 μmol/gcat by using 1%Bi‐0.5%Y‐TiO2 as a photocatalyst. The HCOOH yield was 1.17 times higher than that by using 1%Bi‐TiO2, and 2.23 times higher than that by using pure TiO2. Furthermore, the 1%Bi‐0.5%Y‐TiO2 showed the highest apparent quantum efficiency (AQE) of 4.45%.