The invention discloses a method for governing and improving soda saline and alkaline land through magnet tailing composite modifying agents. Tourmaline powder is accommodated in multiple-hole small cloth bags connected to a long rope and is evenly scattered onto a paddy field surface to make the paddy field surface make sufficient contact with tourmalines, water is completely drained after 4-5 days of field soaking, fresh water is supplemented, soaking is carried out 4-5 days, water is drained, salt leaching is carried out, and the modifying agents are applied, wherein the modifying agents are formed by mixing magnet tailing powder, fermented organic fertilizer and furfural residue; water filling, field harrowing, mud making and transplanting are carried out, and conventional rice cultivation technological management is carried out. The tourmalines are utilized to improve the salt leaching effect and quickly reducing salinity, and water drainage and salt leaching carried out before transplanting is carried out on the soda saline and alkaline land aim to quickly reduce salinity. Because saline-alkali soil is covered with the magnet tailing powder, physical properties of the soil can be changed, rain can more easily infiltrate downwards, surface soil salt can be leached, soil becomes rough in texture, and salt and alkali recovery is prevented. A drip line rises, water can not arrive at the ground directly easily, and salt is prevented from accumulating towards the earth surface. Poor physical characteristics like coldness, poor permeability and adhesion of alkali land are improved, less salt can rise, the soil is loosened, the saline and alkaline land is well improved, and secondary salinization is avoided.