Three-dimensional Ni3S2-reduced graphene oxide (rGO) nanosheets composite is directly grown on nickel foam (Ni3S2-rGO@NF) by a one-step hydrothermal process involving in situ sulfurization of NF and reduction of GO. The introduction of GO is found not only to control the aggregation and the growth of Ni3S2 nanosheets, but also to increase the number of active sites and improve conductivity of composite. The heterogeneous Ni3S2-rGO@NF electrode as electrocatalysts for hydrogen evolution reaction (HER) exhibits significantly enhanced catalytic activity in alkaline media. The onset potential of Ni3S2-rGO@NF can be as low as ∼0 mV, which is comparable to platinum, and only a small overpotential of ∼44 mV is needed to reach a benchmark current density of 10 mA/cm2. Moreover, it demonstrates a good stability. All evidences suggest that the in situ surfurization can be considered as an effective way to prepare metal sulfides as electrocatalysts for hydrogen generation.