The invention discloses a high-intensity concrete admixture. The high-intensity concrete admixture is prepared from the following raw materials in parts by weight: blast-furnace slag 200 parts, edible fungi residues 35-45 parts, gypsum 10-15 parts, gneiss 10-20 parts, shale 25-35 parts, activated carbon slag 30-40 parts, attapulgite 20-30 parts, pine and cypress ash 15-18 parts, polypropylene fibers 2-4 parts, corn stigma 0.2-0.5 part and an additive 1-3 parts. The additive consists of glutinous rice glue, starch octenylsuccinate, fish glue and glucomannan according to the weight ratio of 500: 20: 1-3: 5. The blast-furnace slag is ground granulated blast-furnace slag powder, and the Brinell specific surface area is 500-600 m(2)/kg. The high-intensity concrete admixture has the effects that the compressive property of the concrete is enhanced, the brittleness of the concrete is reduced, and the working preforamnce of the high-intensity concrete is improved.