The invention relates to the technical field of concrete, and particularly discloses high-strength light porous concrete and a preparation method thereof. The high-strength lightweight porous concreteis prepared from the following raw materials in parts by weight: 350-400 parts of cement, 700-800 parts of sand, 1100-1200 parts of stones, 170-230 parts of a mineral admixture, 220-280 parts of water, 20-30 parts of coarse whiting, 25-40 parts of straw fibers, 15-30 parts of kaolin, 5=10 parts of a foaming agent, 12=18 parts of a tackifier, 4=8 parts of expanded perlite and 3=5 parts of a waterreducing agent. The mineral admixture is prepared from the following raw materials in parts by weight: 50-70 parts of steel slag, 30-50 parts of fly ash and 90-110 parts of slag; the preparation method comprises the following steps: fully foaming the foaming agent through a foaming machine, and uniformly mixing the foam with cement paste to prepare the high-strength light porous concrete. According to the concrete, closed foam holes are formed in the concrete so that the lightweight effect is achieved, and the added straw fibers and mineral admixtures can improve the mechanical strength of theconcrete.