The invention discloses a high performance concrete with steel slag as an admixture and aggregate and a preparation method thereof. The concrete is composed of a cementing material, aggregate, a water reducer and mixing water. The cementing material is prepared by compounding, by mass, 50 to 80% of cement, 10 to 30% of superfine steel slag powder and 10 to 30% of superfine mineral slag, wherein the specific surface areas of the superfine steel slag powder and the superfine mineral slag are respectively controlled to be 400 to 600 m<2>/kg and 400 to 500 m<2>/kg. The aggregate is composed of broken stone, steel slag sand and river sand, wherein the particle size of the steel slag sand is 5 to 10 mm, the steel slag sand is used to partially replace the broken stone, and the addition amount of the steel slag sand is 20 to 50%. The high efficiency water reducer is dissolved in water in advance and then added with the mixing water. The preparation method provided by the invention is simple and can prepare concrete with a grade in a range of C20 to C60 and substantially improve the comprehensive utilization rate of the steel slag; and the prepared concrete has good work performance, mechanical properties, etc. and substantially improved endurance.