The photocatalytic overall conversion of CO2 with H2O to chemical fuel and oxygen mimicking natural photosynthesis is a huge challenge in photocatalysis. This work shows the achievement of the solar-driven photo catalytic overall CO2 reduction with H2O to CO and O-2 over a Persian buttercup-like BiOBrxCl1-x solid solution. A CO generation rate of 15.86 mu mol g(-1) h(-1) with the approximate stoichiometric O-2 evolution is yielded on BiOBr0.6Cl0.4 solid solution under simulated solar light irradiation, which was about 7.5 and 10.2 times higher than that of pure BiOCI (2.11 mu mol g(-1) h(-1)) and BiOBr (1.55 mu mol g(-1) h(-1)), respectively. The enhanced photoactivity is contributed to the mediate band gap and energy level tuned by the formation of BioBr(x)Cl(1-x) solid solution to facilitate the separation of photogenerated charges. Besides the unique electron structure, the photoinduced oxygen vacancy (O-v) formed on BiOBrxCl1-x solid solution also plays an important role in the CO2 reduction.