Transition carbides have been studied as one of the most promising non-precious-metal catalysts for hydrogen evolution reaction (HER) due to analogous electronic structure to precious metals. Herein, molybdenum carbide nanoparticles supported on nitrogen-doped carbon (Mo2C/NC) have been successfully synthesized through a facile and environmentally-friendly hydrothermal method. The nitrogen content is adjusted by varying the molar ratio of glucose (G) and glucosamine hydrochloride (GH). With an optimal G/GH ratio of 0.6, Mo2C/NC-0.6 nanoparticles exhibit a low onset reduction potential of 95 mV with a Tafel slope of 79.2 mV dec(-1), an over potential of 168 mV at cathodic current density of 10 mA cm(-2) and good stability in acidic media. The high electrocatalytic activity of Mo2C/NC-0.6 can be attributed to high specific surface area, synergistic effect between Mo2C and N species, and the conductive N-doped carbonaceous matrix. This study may provide a promising strategy for synthesizing efficient water splitting catalysts with great electrocatalytic activities.