Graphitic carbon nitride with nitrogen vacancies(NV-g-C3N4) as a photocatalyst has been studied in solar-driven energy conversion.However,expensive and rare noble metal co-catalysts such as Pt or Pd are required in the photocatalytic H2 evolution.Consequently,the exploration of low-cost and high-performance co-catalysts to replace expensive and rare noble metals has received more and more attention.Herein,a novel hierarchical porous NiO anchored on NV-g-C3N4 is successfully fabricated.The NV-g-C3N4/NiO photocatalysts exhibited outstanding H2 evolution rate under visible light irradiation in absence of noble metal co-catalysts.The optimized NV-g-C3N4/NiO (the mass ratio of NiO is ～ 1.7％) achieved a maximum H2 evolution rate of 170.60 μmol·g-1·h-1,exhibiting ～ 8.3-fold enhancement as compared to that of NV-g-C3N4.NiO as co-catalyst pro-vided more active sites for photocatalytic H2 evolution.Moreover,on the interface of NV-g-C3N4/NiO,an interface electric field is formed between NiO and host nitrogen-va-cated g-C3N4,facilitating the transfer of the photogenerated electrons from NV-g-C3N4 to NiO co-catalyst,resulting in significantly promoted migration and separation efficiency of the photogenerated charge carriers.