A composite catalyst (Ni-NiO@CN) with nickel-nickel oxide (Ni-NiO) loaded on two-dimensional g-C₃N₄ (CN) was successfully constructed by hydrothermal coupled pyrolysis. The Ni-NiO nanostructure served as the methanol oxidation reaction (MOR) active center, and the N-rich CN matrix promoted electron transfer and effectively protected the active components from shedding through physical isolation. Ni-NiO@CN-500, obtained by calcination at 500 ℃, exhibited the highest activity with the current density of 164 mA·cm^-2 at 1.67 V (vs RHE) in the alkaline medium. Furthermore, the current density of Ni-NiO@CN-500 could be maintained at 154.9 mA·cm^-2 (94.5% of its initial value) in the CO-saturated alkaline methanol electrolyte, significantly outperforming commercial Pt/C catalysts.