The invention discloses a foamed aluminum semi continuous vacuum foaming device and method, and belongs to the field of foam metal material. The foamed aluminum semi continuous vacuum foaming device is composed of three parts: a tundish, an initial pore generation device and a vacuum foaming furnace. The tundish and the initial pore generation device are in seamless connection, and the initial pore generation device and the vacuum foaming furnace are in semi continuous connection. During preparation of foamed aluminum, firstly a tackified aluminum alloy melt is introduced in the tundish and is kept at a certain liquid level height, then air is introduced into the initial pore generation device having the same liquid level height to make initial pores generated in the tackified aluminum alloy melt, finally, the melt is allowed to flow into a preheated stainless steel crucible in the vacuum foaming furnace in a semi continuous mode, and melt foams are cooled and solidified to obtain the foamed aluminum. The foamed aluminum semi continuous vacuum foaming device is adopted to prepare the foamed aluminum, has the characteristics of high efficiency and low cost, and can realize semi continuous industrialization production of the foamed aluminum.