The invention provides a method for recovering iron resources in steel slag. The method comprises the following steps that 1, the steel slag is subjected to melting operation; adjustable and controllable oxidizing gas is sued and is sprayed and blown to the liquid surface of the steel slag; FeO in the steel slag is oxidized; 2, the reacted steel slag is subjected to temperature reduction operation; after the temperature is stable, heat insulation is performed; 3, the steel slag after the heat insulation is cooled. After the steps, a finally generated MgFe2O4 spinel phase and Fe3O4 are major iron containing phases in the used steel slag. Through the treatment steps provided by the invention, (1) the iron grade in the steel slag after magnetic separation is obviously improved; the steel slagcan be used as iron ore resources for steel and iron production; (2) compared with a common steel slag iron resource recovery treatment method at preset, the method has the advantage that the yield of iron in the steel slag is greatly improved; (3) the steel slag quantity of the aftertreatment is obviously reduced; the effect of steel slag solid waste reduction is achieved.