The invention provides a preparation method of porous nickel. The preparation method is characterized by comprising the steps: melting pure nickel and pure zinc in a crucible by specified proportions to obtain a nickel-zinc alloy melt, adjusting the temperature of the melt to the range from 950 DEG C to 1000 DEG C, casting in a copper mold, and then performing vacuum evaporation on the obtained nickel-zinc alloy to obtain the material, namely the porous nickel material. The method has the advantages of simple process, low environmental pollution, adjustable pore size and porosity and the like.