The invention provides a Ni/SiCNWs/CNFs flexible composite electrode material as well as a preparation method thereof. The method comprises the following steps: mixing PAN (Polyacrylonitrile) and DMF(N,N-dimethylformamide), and stirring to obtain a yellow viscous solution, then using a electrospinning method to obtain a carbon nanofiber precursor, and controlling the conditions of pre-oxidation and carbonization to control the flexibility of a material so as to obtain a carbon nanofiber skeleton; taking nickel nitrate hexahydrate as a nickel source; taking silicon powder and carbon powder asa silicon source and a carbon source respectively; putting the silicon source, the carbon source and the carbon nanofiber flexible material precursor into a graphite crucible, putting the crucible into a high-temperature tube furnace, reacting under an argon atmosphere, and cooling to obtain the flexible composite electrode material. The composite material has high strength, high specific surfacearea and high catalytic activity. The invention provides the efficient, simple and low-cost method for preparing a flexible Ni-based catalytic electrode.