The invention relates to a low-bleeding-rate pumpable phosphogypsum and yellow phosphorus slag filling paste and a preparation method of the paste. The paste is prepared by adding a certain percentage of yellow phosphorus slag as a cementing material into industrial waste residue phosphogypsum as a filling aggregate, calculating the required amount of water according to the target concentration on the basis that the natural moisture content of the phosphogypsum is determined, adding water and stirring. The filling paste has the advantages of precise concentration control, relatively low bleeding rate, relatively good fluidity, certain early strength and relatively good middle-term strength and long-term strength, and is used for the paste filling of phosphorite underground mined-out areas; the bleeding rate of slurry for phosphogypsum underground cementing filling is reduced, cost of underground drainage and filling is lowered and the pollution to the mine water environment is reduced. According to the invention, the industrial waste residue phosphogypsum and yellow phosphorus slag can be fully and effectively utilized, requirements on filling operation of phosphorus resource mining are met, the production capacity of a mine is enlarged, economic benefits are increased, the ground accumulation of industrial waste residue is reduced, the occupancy rate of land is lowered and the secondary pollution of filling wastewater to the environment can be effectively reduced.