The invention discloses a simultaneous phosphorus and nitrogen removal light material, a preparation method and the application thereof, and belongs to the technical field of environment function materials and sewage disposal. A fusion mixture is obtained by sufficiently fusing and dispersing sulfur and an iron-based component, wherein the iron-based component is a pyrite and calcium magnesium carbonate mixture; and foaming treatment is carried out on the fusion mixture to form the simultaneous phosphorus and nitrogen removal light material. The simultaneous phosphorus and nitrogen removal light material disclosed by the invention has the characteristics of high porosity, large specific surface area, light weight and high reaction activity. The obtained light material, as a microbial carrier and an electron donor of biochemical reactions, is applied to the reactors, such as fixed beds and fluidized beds, for sewage disposal, and has the advantages of good microorganism adhesion property, high denitrification speed and good phosphorous removal effect.