Abstract: Comprehensive utilization of phosphogypsum is of great commercial value and practical significance for environmental safety,effective use of resources,and technology security of sustainable development of phosphate fertilizer industry.Impurities,such as phosphorus pentoxide,fluorine,and organic impurities,in phosphogypsum hinder the use of phosphogypsum.In order to find a simple,economical,environment-friendly method to remove phosphorus in phosphogypsum,reaction conditions,such as mass fraction of sulfuric acid,temperature,time,and liquid-solid ratio,that using sulfuric acid to leach phosphogypsum and effects of these conditions on mass fraction of undissolved phosphorus pentoxide in phosphogypsm were studied respectively.Optimum conditions were confirmed by single factor analysis and orthogonal experimental design.Optimum conditions were as follows:mass fraction of H<SUB>2</SUB>SO<SUB>4</SUB> is 20%,reaction temperature is 80 ℃,mass volume ratio of liquid to solid is 2 mL/g,and reaction time is 4.5 h.Under these conditions,mass fraction of P<SUB>2</SUB>O<SUB>5 </SUB>reduced by about 99%,and down to 0.005% below.