Stainless steel slag foam concrete was prepared using the stainless steel slag, cement, fly ash, foaming agent and water as raw materials. Chemical composition, micro morphology, mineral composition, structural, free CaO content, grindability, internal exposure index and external exposure index, activity index of the stainless steel slag and foam concrete were tested. In addition, the main performance parameters of the prepared foam concrete, such as compressive strength, dry density and heat conduction coefficient, leaching concentration of heavy metals were also studied. The results showed that the stainless steel slag had certain cementitious activity and good grindability owing to mineral composition of Ca2SiO4. The internal exposure index and external exposure index of the foam concrete satisfied the requirements of the limits of radionuclides in building materials, although it contained Al and heavy metals of Ti, Cu, Pb, Ta, etc. The dry density was 597?621 g/cm3, compressive strength was 1.83?2.98 MPa after curing 28 d and heat conduction coefficient was 0.11?0.12 W/(m?K), which satisfied the requirements of foam concrete, when 25wt%?42wt% stainless steel slag was used in the foam concrete. The main heavy metals in the stainless steel slag mainly existed as stable solid metals. The leaching concentration of heavy metals from the foam concrete was much lower than the limit value of the identification standards for hazardous wastes. Therefore, it was safe and feasible to utilize the stainless steel slag to produce foam concrete.