The invention discloses a method for recovering iron in fayalite metallurgy slag through roasting of iron pyrite. The method comprises the steps that the iron pyrite is added into the fayalite metallurgy slag, leaching is conducted by means of an acid solution after oxidizing roasting of the iron pyrite is conducted at the temperature of 300-1100 DEG C, and the leaching rate of iron is equal to or higher than 94%; or strong magnetic separation is conducted, and the content of iron in magnetic concentrate reaches 66%. According to the method, the iron in the fayalite metallurgy slag and iron in pyrite cinder are effectively recovered through natural oxidizing roasting of the iron pyrite, and the method has an obvious effect on minimization and reclamation of the fayalite metallurgy slag and the pyrite cinder.