The search of efficient and stable photocatalysts for the evolution of hydrogen from water using solar energy is of great importance for material science today. Limited by the relatively inferior stability of oxynitrides, the availability of these visible-light-response materials in photocatalysis is still far below what is expected. Here we report a novel oxynitride Ce0.3Zr0.7O1.88N0.12 as an efficient and stable H-2-evolving photocatalyst under visible light irradiation, which can further enable overall water splitting by coupling with an O-2-evolving photocatalyst via Z-scheme. Experimental and theoretical results together reveal that the origin of the excellent activity and stability of Ce0.3Zr0.7O1.88N0.12 photocatalyst can be attributed to the improved separation rate of photoexcited charge carriers by surface and sub-surface oxygen vacancies. The present study provides a strategy to engineer efficient and stable photocatalysts, and the oxynitride mentioned above could act as a promising candidate of H-2-evolving photocatalyst for designing a prominent Z-scheme photocatalytic system.