The invention discloses a steam-cured high-performance foam concrete block which comprises 55-60% of cement, 7-9% of slag powder, 5-8% of sand, 0.5-1.0% of a water reducing agent, 0.88-3% of a curing agent, 0.06-0.3% of a foaming agent and 24-26% of water, wherein the mass of the slag powder is less than 20% of that of the cement which is P.O42.5R cement. According to the foam concrete block, the curing agent is used, so that structural pulverization, collapse of dies and the like are avoided, and the steam-curing effect is improved; water-proof, heat preservation and thermal insulation effects of products are good, and building energy saving is facilitated; the products have good durability and the same service life with a main construction; and the problems of low strength, pulverization, large shrinkage, collapse of dies and the like of low-density foam concrete are solved.