The invention discloses a method used for extracting iron from red mud by drastic reduction and a method used for preparing a gel material from secondary tailings, and belongs to the field of comprehensive utilization of resources. The method used for extracting iron from red mud by drastic reduction comprises following steps: Bayer process red mud is dried and crushed; the crushed red mud is mixed uniformly with a reducing agent and an auxiliary agent; the mixture is subjected to drastic reduction in a sealed container in a kiln with oxidizing atmosphere or reducing atmosphere; and the cooled material prepared by reduction reaction is subjected to wet milling and magnetic separation so as to obtain the iron powder of drastic reduction with iron grade of 90% or more, and iron recovery rate of 90% or more. The method used for preparing the gel material from secondary tailings comprises following step: the secondary tailings obtained after magnetic separation is dried, and are mixed uniformly with blast furnace slag, cement clinker, an exciting agent and an early strength agent; and then the secondary tailing gel material is prepared, wherein compressive strength and breaking strength of the secondary tailing gel material both meet the requirements of composite Portland cement 325 standard. According to the methods of the invention, the large amount of residual iron is recycled from the red mud, and the secondary tailings are used for preparation of the gel material, so that waste is transformed into valuables, the recovery of red mud iron resource is realized, and a problem of accumulation of red mud is solved.