Abstract: It was studied that the effect of the quantity of steel slag and silica fume on concrete strength and fluidity as well as the rule of the strength of concrete with steel slag and silica fume. Adopting grade 42.5 ordinary portland cement, medium sand, 5～25mm broken stone, proper quantity of NF-2-6 retarding high effect water-reducing agent, water cementitious materials ratio 0.26, 10% of steel salg and 10% of silica fume, or water cementitious materials ratio 0.24～0.31, 10%～30% of steel slag, 15% of silica fume, C80 high performance concrete can be prepared. A reference formula for concrete commercial mix was also given.