Tungsten carbide (WC) is an alternative to the costly and resource-constrained Pt-based catalysts for hydrogen evolution reaction (HER). In this work, a one-step facile and easily scalable approach is reported, to synthesize ultrafine WC by molten salt. Benefiting from the ideal synergistic catalytic effect between the highly active WC nanoparticles and the conductive graphitic carbon, and strong charge transfer ability, the unique WC/C hybrids demonstrated excellent HER performance in both acid and alkaline medias with overpotentials of 112 and 122 mV, at a current density of 10 mA cm and Tafel slopes of 54.4 and 68.8 mV dec, in acid and alkaline media, and remarkable stability. With the simplicity and low-cost of the synthetic approach, the strategy presented here can be extendable to the preparation of other transition metal-based/carbon hybrids for versatile applications.