The invention discloses a method for preparing concrete by taking manganese residue-steel residue-limestone powder as admixture. Raw materials comprise cementing material, aggregate, admixture and water. The cementing material is formed by compounding cement, manganese residue, steel residue and limestone powder, and an activator is an alkaline activator or a sulphate activator, specific surface areas of manganese residue micro power, steel residue micro power and the limestone powder are respectively controlled to be 400-600m<2>/kg, 500-800m<2>/kg and 600-900m<2>/kg. Small particle size continuous grading coarse aggregate is adopted, and the content of 5-20mm broken stone is higher than 85%. The activator is dissolved in water in advance and is doped with mixing water. The obtained concrete has good working performance, strength in 28 days is improved by about 8% compared with the concrete which independently adopts fine slag powder, cost is reduced by nearly 20%, durabilities such as contractility resistance, freezing resistance, marine denudation resistance and the like can be obviously improved. The process in the invention is simple, C20-C60 grade concrete can be prepared, industrial waste residue doping content in the concrete can be obviously improved, and good practical value can be obtained.