Herein, ternary nickel cobalt oxide (NiCo2O4) was firstly employed to increase the photocatalytic water reduction ability of g-C3N4. 17.5 wt%-NiCo2O4/g-C3N4 shows excellent water splitting performance with a H-2 production rate of 5480 mu mol h(-1) g(-1), which is extremely better than that of Co3O4, NiO, Pt modified g-C3N4. The quantum efficiency of 17.5 wt%-NiCo2O4/g-C3N4 can reach 4.5% under 400 (+/- 7.5) nm light irradiation. The greatly increased activity of 17.5 wt%-NiCo2O4/g-C3N4 can be attributed to the richer active sites and the superior electrical performance provided by co-existing nickel and cobalt ions with multivalent state. Moreover, the activity of composite almost shows no significant weaken even after 20 h irradiation. A Z-scheme route was put forwarded for H-2 production over NiCo2O4/g-C3N4 instead of the traditional p-n junction based on our study.