The invention relates to a
red mud composite material which comprises components in parts by weight as follows: 60-78 parts of
red mud, 8-12 parts of a cementing material, 8-24 parts of an inorganic addition material, 2-8 parts of a natural
fertilizer, water and a pore forming agent, wherein the
mass of water is 50%-55% of total weight of the
red mud, the cementing material, the inorganic addition material and the natural
fertilizer, and use amount of the pore forming agent is 0.1%-0.3% of the
mass of water. The invention further relates to a preparation method of the red mud
composite material and a repairing method of the red mud
composite material for soil polluted by heavy
metal. The red mud composite material is simple in preparation process, abundant in
raw material source and reasonable in proportion, so that the red mud and agricultural
solid wastes are utilized sufficiently, and the comprehensive utilization of resources is achieved.