Recently, the first-row transition metal dichalcogenides MX2 (M = Fe, Co, Ni; X = S, Se) have been widely reported as promising catalysts for hydrogen evolution reaction (HER) because of its excellent catalytic activity and earth-abundance. The rational nanostructure designs have been proved as an effective way to improve their catalytic performance. However, the reported one dimension (1D) NiS2 nanowires for HER suffer from a large Tafel slope. Here, we report a facile synthesis of 1D NiS2 nanowires and its high efficient catalytic activity in HER. This nanowire structure with large surface area and active sites enables highly efficient electrocatalytic performance in HER with a much smaller Tafel slope (83.5 mV/dec) compared to that of bulk NiS2 (136 mV/dec) as well as long-term stability. Our work builds up a structure performance relationship and enriches the synthetic strategy to other efficient catalysts such as first-row transition metal dichalcogenides or transition metal phosphide. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.