A visible-light-induced hydrogen evolution system based on a CdSe quantum dots (QDs)–TiO₂–Ni(OH)₂ ternary assembly has been constructed under an ambient environment, and a bifunctional molecular linker, mercaptopropionic acid, is used to facilitate the interaction between CdSe QDs and TiO₂. This hydrogen evolution system works effectively in a basic aqueous solution (pH 11.0) to achieve a hydrogen evolution rate of 10.1 mmol g⁻¹ h⁻¹ for the assembly and a turnover frequency of 5140 h⁻¹ with respect to CdSe QDs (10 h); the latter is comparable with the highest value reported for QD systems in an acidic environment. X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and control experiments demonstrate that Ni(OH)₂ is an efficient hydrogen evolution catalyst. In addition, inductively coupled plasma optical emission spectroscopy and the emission decay of the assembly combined with the hydrogen evolution experiments show that TiO₂ functions mainly as the electron mediator; the vectorial electron transfer from CdSe QDs to TiO₂ and then from TiO₂ to Ni(OH)₂ enhances the efficiency for hydrogen evolution. The assembly comprises light antenna CdSe QDs, electron mediator TiO₂, and catalytic Ni(OH)₂, which mimics the strategy of photosynthesis exploited in nature and takes us a step further towards artificial photosynthesis.