The invention provides a preparation device and method of a low-smelting-point foam metal and the low-smelting-point foam metal. The device comprises a sealed vessel which is filled with granular filling materials, wherein a plurality of pores are formed in a vessel cover of the sealed vessel and are used for pouring molten low-smelting-point liquid metal; the molten low-smelting-point liquid metal enters the sealed vessel and then automatically fills clearances reserved among the granular filling material based on essential mobility; when the liquid metal fills all the clearances and is cooled and solidified, a mixture of the solidified metal and the filling material is moved out from the sealed vessel, and the filling material in the mixture is removed, and thus a porous metal frame which is the foam metal can be obtained. The low-smelting-point foam metal prepared by the method is simple and quick to prepare; the requirement on the temperature technology is small; the process is easily operated and controlled; the porosity of the obtained foam metal is high; the structure is light; the performance is high; and the low-smelting-point foam alloy is applicable to a plurality of fields and industries.