Hydrogenated SrTiO3/TiO2(H:(STO/TiO2)) with unique heterostructured arrays was prepared, followed by the immobilization of plasmonic Au nanoparticles to form robust composite photoelectrodes. The synergistic effects of heterocoupling of perovskite-type STO on TiO2nanotube arrays and plasmonic Au-decoration substantially improved the photocatalytic performance with visible light. In contrast to pure TiO2, H:(STO/TiO2) facilitated an efficient transfer of electrons between STO and TiO2, and decreased the recombination ratios of photoexcited electron-hole pairs. Plasmonic Au also effectively boosted the photoresponse under irradiation with visible light. Photocurrent density of 2.3 mA cm-2under visible light irradiation (λ > 400 nm) with IPCE peaking at 17% and a concomitant apparent quantum efficiency of 3.5% in the 580-680 nm region was achieved. Faradaic efficiency was estimated to be about 80% at the oxygen evolution rate of 18.5 μmol cm-2h-1under simulated sunlight irradiation (AM1.5G, 100 mW cm-2). With the aid of X-ray absorption spectra in situ and ultrafast transient absorption spectra, the detailed understanding of the underlying mechanism during photoinduced processes in Au/H:(STO/TiO2) is well elucidated.