Abstract: In recent years, molybdenum carbide (Mo₂C) has been widely used in the field of hydrogen evolution in water electrolysis due to its good stability and Pt-like properties. However, the excess growth of Mo₂C under high-temperature poses a negative impact on its catalytic activity. To cope with this, polysaccharide guar gum is used as the carbon source to inhibit the agglomeration of molybdenum atoms in the process of high temperature treatment by the strong coordination of hydroxyl and molybdate in its molecular structure; at the same time, the introduction of nitrogen can further improve the electron transfer rate and catalytic properties of carbon substrate. The results show that the composite structure of ultra-fine Mo₂C@N-doped carbon nanosheets can be obtained at 800 ℃, whose overpotential is 163 mV at the current density of 10 mA/cm² in the alkaline medium and Tafel slope is 64.8 mV/(°). The material system shows good stability. After a 12-hour endurance test, the current density of electrode material is seen no obvious attenuation. The preparation method is expected to provide a new idea for the synthesis of other ultra-fine metal carbide systems.