The invention relates to an iron tailing soil improvement agent and an iron tailing soil improvement method. The iron tailing soil improvement agent comprises biochar, rice husks, ceramsite, organic fertilizers, attapulgite powder and planting soil. A mass ratio of the biochar to the rice husks to the ceramsite to the organic fertilizers to the attapulgite powder to the planting soil is (0.5-3):(0.2-1):(0.5-1.5):(1-4):(1-2.5):(1.0-2.2). The iron tailing soil improvement agent and the iron tailing soil improvement method have the advantages that the particle size of soil can be improved by theaid of the iron tailing soil improvement agent, the loss rate of water in the soil can be eased, the water retention capacity can be enhanced, organic matters can be quickly and effectively supplemented, the content of organic matters in tailing can be effectively increased, and suitable environments can be provided for plant growth; the rice husks and the ceramsite are matched with one another, the porosity of iron tailing soil can be improved, the hardening degree of the soil can be lowered, the tailing soil can keep in excellent gas-permeable and soft states for a long term, accordingly, the iron tailing soil improvement agent and the iron tailing soil improvement method are favorable for respiration of animals and plants in the soil, and the survival rate can be increased.