Based on the fact that nitrogen defective can greatly affect the electronic structure and the properties of photo-excited charge transmission and plays a substantial role in photocatalysis, defect-induced graphite nitride carbon (g-C3N4-x(X)NiS2) was synthesized by a facile one step with sodium hydroxide-assisted route in this paper. The photocatalytic activity of nitrogen defective g-C3N4-x(0.1)NiS2 composite photocatalysts exhibited much more high activities, namely, the maximum amount of H-2 production was reached up to 143.5 A mu mol under continuous visible light irradiation for 5 h, which is about 72 times of pristine g-C3N4 photocatalyst and two times of g-C3N4(0)NiS2 composite photocatalysts. Such high enhanced abilities were greatly attributed to the nitrogen defective on the photocatalysts. A series of characterizations such as SEM, TEM, XPS, XRD, BET, FTIR, UV-vis diffuse reflectance spectroscopy (DRS), photocurrent and transient fluorescence etc. were conducted and the results of which were in fully congruent with each other. Furthermore, the possible reaction mechanism over nitrogen defective g-C3N4-x(X)NiS2 composite photocatalyst under visible light irradiation was proposed. [GRAPHICS] .