In order to comprehensively utilize steel solid waste, this paper used steel slag, blast furnace slag, iron tailings and natural crushed sand as raw materials, NaOH and Na2SiO3 as activators to prepare concrete. The effects of mass ratio of steel slag-to-blast furnace slag, iron tailings replacement rate, alkali dosage and alkali modulus on the working and mechanical properties of concrete were investigated. Based on microstructural analysis and pH test, the corresponding hydration mechanisms of alkali-activated steel solid waste concrete were revealed. The results show that the addition of iron tailings can improve the gradation of aggregates particles and enhance the overall compactness of concrete. The activators promote the dissolution of active minerals of steel slag and blast furnace slag, and speed up the hydration reaction process of concrete. The inclusion of steel slag can provide abundant Ca2+ for the formation of C-S-H gel, C-A-S-H gel and Ca(OH)2 crystal. When the mass of steel slag-to-blast furnace slag is 1∶9, the iron tailing replacement rate is 45% (mass fraction), the alkali dosage is 6% (mass fraction) and the alkali modulus (molar ratio of SiO2 and Na2O) is 1.4, the 28 d compressive strength of alkali-activation steel solid waste concrete reaches 47.6 MPa.