As a typical solid waste in iron and steel industry, steel slag has been difficult to be consumed and utilized on a large scale for a long time. In this paper, steel slag and fly ash are used as main raw materials to prepare light wall materials by multiple excitation technology. The effects of raw material formula, specific surface area of steel slag powder, type and dosage of activator and curing system on the compressive strength of samples are studied. The hydration mechanism of cementitious system is studied by XRD and SEM. The results show that the compressive strength of the samples can be improved by appropriately increasing the initial curing temperature, increasing the specific surface area of steel slag powder and adding activator. The sodium silicate solution with a modulus of 1.2 is used as the alkaline activator, under the condition that the ratio of steel slag powder, fly ash, clinker powder and gypsum powder is 70:10:15:5, the dosage of alkaline activator and aluminum sulfate is 2% of the solid mixture, the specific surface area of steel slag powder is 516 m²/kg, after initial curing at 50 ℃ for 7 days, the sample density is 821 kg/m³. The compressive strength of 28 d can reach 3.98 MPa, and the main indicators meet the requirements of the specification of “Light Partition Wall Insulation Strips for Buildings” (GB/T 23450—2009). Under the action of multiple excitations, a large amount of C-S-H and AFt will be produced, which will join other hydration products to form a compact whole, greatly improving the strength of the cementitious system.