A new ABO(3) perovskite photocatalyst BaZn1/3Nb2/3O3 has been synthesized by a solid-state reaction process. Nine Raman active vibration modes observed from its Raman scattering spectrum suggest that BaZn1/3Nb2/3O3 possesses a distorted perovskite structure. The formation rate of H-2 evolution from CH3OH/H2O solution with 5.0 wt % Pt cocatalyst under the irradiation of a 400 W Hg lamp is about 2685.7 mumol/(h(.)g catal). for the photocatalyst BaZn1/3Nb2/3O3. It also splits pure water into H-2 and O-2 in a stoichiometric ratio with NiOx and RuO2 cocatalysts under UV light irradiation. The formation rates of the H-2 and O-2 evolution from pure water in the case of 1.0 wt % NiOx cocatalyst under UV light irradiation are 291.22 and 145.61 mumol/(h(.)g catal), respectively. The photoelectrochemical properties of BaZn1/3Nb2/3O3 film as deposited by using a pulsed laser deposition (PLD) technique suggested that the lower conduction band should be composed of the Zn2+ 4s state, which is in good agreement with its UV-vis diffuse reflectance spectrum.