The invention relates to the technical field of cements, and concretely relates to a foaming cement slab and a preparation method thereof. The foaming cement slab is mainly prepared from the raw materials: 60 to 70 parts of cement, 10 to 15 parts of tetrasodium iminodisuccinate, 10 to 15 parts of ethylene diamine tetraacetic acid dipotassium ethylene dinitrilotetra-acetic acid, 10 to 15 parts of potassium chromate, 5 to 10 parts of tetrahydro-iso-humulone, 5 to 10 parts of 4,4-diphenylhydrazine diphenyl ether4,4-disulfonylhydrazide diphenyl ether, 5 to 10 parts of 4,4'-p-sulfonylhydrazide diphenyl ether 4,4'-oxybis(benzenesulfonyl hydrazide), 2 to 4 parts of sodium alkyl sulfate, 2 to 4 parts of heavy sodium alkyl benzene sulfonate, 0.3 to 0.5 part of sodium polymethacrylate, 0.3 to 0.5 part of sodium amine sulfonate, 0.5 to 0.7 part of 2,3-dihydrobutanedioic acid, 0.5 to 0.7 part of sodium hexametaphosphate, and the like. The preparation method comprises the steps of mixing the raw materials, injection molding, maintaining, demoulding and the like, and is simple in process and easy to operate. The foaming cement slab provided by the invention is low in heat conductivity coefficient, light in weight, less in water consumption, prolonged in initial setting time, sufficient in foaming, waterproof, and better in heat insulation and sound insulation effects.