The invention relates to a production method of a foamed concrete block manufactured from steel slag. The work flow comprises the following steps: 1, taking tailing steel slag after iron dressing; 2, grinding; 3, mixing dry powder; 4, pulping, mixing, and stirring; 5, performing casting molding; 6, foaming; 7, performing static curing; 8, cutting; and 9, performing standard curing. The production method comprises the following specific steps: crushing the steel slag, screening, performing magnetic separation, grading, and drying; performing water quenching on blast furnace slag, and drying; mixing the ground steel slag and ore slag powder with cement clinker, gypsum, lime and the like according to certain weight percents, wherein the ground tailing steel slag powder accounts for 20-60%, the ground ore slag powder accounts for 20-55%, the natural gypsum accounts for 4-10%, the lime accounts for 3-9%, and the cement clinker accounts for 6-12%; mixing and stirring the raw materials, adding water of 40-60 DEG C, and quickly stirring for 1-2 minutes; adding gas-forming aluminum powder, uniformly stirring, and pouring into a mold; and placing in a steam curing box, performing gas forming and steam curing, dismounting the mold, cutting, and curing at normal temperature for 7-12 days. The invention has the following advantages: the produced foamed concrete block meets the requirements of standards; the production cost is low; and comprehensive utilization of resources, energy saving and emission reduction are realized.