•A novel monovalent copper-based SrCu1.88□0.12O1.94□0.06 photocatalyst containing Cu and O vacancies was designed for the first time.•SrCu1.88□0.12O1.94□0.06 photocatalyst is rich in pore structure and covered with a layer of nanosheets.•The mechanism of vacancies enhanced photocatalytic performance was proposed based on DFT. A novel SrCu□O□ photocatalyst containing Cu vacancy and O vacancy was synthesized for the first time based on solid-phase sintering. The crystal structure, elemental composition, microscopic morphology, optical properties and energy band structure of the samples were characterized and analyzed in detail. The vacancies in the material were determined by ICP-MS and EPR, first-principles calculations showed that the introduction of vacancies extends the forbidden band of the photocatalytic to the visible band. The photocatalytic performance of SrCu□O□ was evaluated by degrading MB and TCHCI. Our results show that SrCu□O□ enhances the degradation performance of organic compounds due to rich vacancies that promote electron-hole pair separation and improve photogenerated carrier separation efficiency. Vacancy-containing metal oxide catalysts have broad application value in environmental remediation. Display omitted