The invention provides a preparation method of zinc-aluminum alloy foam, and belongs to the field of porous metal materials. By aiming at the defects that when the existing flux foaming method is adopted for preparing foam metal, foaming agents and the foaming temperature are not matched, the dispersion of the foaming agents is difficult, the viscosity increase process is complicated, and the metal brittleness is improved through excessive viscosity increase phases, a zinc-aluminum alloy semi-solid stirring method is adopted, the foaming agents are added and dispersed at a lower temperature, and then, the foaming is carried out at a high temperature of the zinc-aluminum alloy fusing point for preparing the zinc-aluminum alloy foam. The method has the characteristics that the hole structure is controllable, the process is simple, the cost is low, and the industrialized production can be realized.