The invention relates to an ultra-thin carbon-layer composite material modified by nickel nanoclusters and vanadium carbide particles, and its preparation method and application. The composite material comprises a two-dimensional ultra-thin carbon-layer as a matrix, in which nickel clusters and vanadium carbide nanoparticles are embedded to form coupling interfaces between Ni and C, VC and C, and Ni and VC. The thickness of the two-dimensional ultra-thin carbon-layer is less than 10 nm.