The invention relates to the technical field of building materials, in particular to a light wall material prepared by recycling waste alkali residues and a method. Various light wall padding materials such as light wall bricks, wall plates and wall building block materials are prepared mainly based on the light principle of a large quantity of waste alkali residues in marine chemical enterprises, and the prepared various light wall materials can reach higher strength than that of aeration building blocks. The light wall material does not need to be heated with steam and can be prepared into bricks and building block in various shape and large wall plates, the production efficiency is high, sintering through a boiler is not needed, steam foaming is not needed, energy conservation and environment friendliness are achieved, and the manufacturing cost is low. The prepared light wall material can be widely applied to padding high-rise buildings and has excellent economic benefits. The world-wide environment-friendly problem that alkali residues cannot be recycled is solved.