Photocatalytic hydrogen evolution is considered as one of the promising pathways to settle the energy crises and environmental issues by utilizing solar energy. In this paper, noble-metal-free Ni2P was used as cocatalyst to enhance g-C3N4 for photocatalytic hydrogen production under visible light irradiation (>420nm). Characterization results indicated that Ni2P nanoparticles were successfully loaded onto g-C3N4, which can significantly contribute to accelerate the separation and transfer of photogenerated electron. The hydrogen evolution rate reached approximate to 270 mu molh(-1)g(-1) and the apparent quantum yield (AQY) was approximate to 2.85% at 420nm. Meanwhile, there is no obviously decrease of the hydrogen production rate even after 36h under visible light illumination. In addition, the mechanism of photocatalytic hydrogen evolution was also elaborated in detail. [GRAPHICS] .