During the mining of ion-type rare earth resources in southern China, regional ammonia nitrogen pollution in water environment caused by the migration and diffusion of ammonium sulfate has become a key bottleneck restricting the sustainable development of ion-type rare earth resources. "Two-stage percolation coupling biological system" is a widely used, stable, and cost-controllable process for the treatment of ion-type rare earth mine tailings. High-performance mixed adsorption filter material is the focus of process optimization and upgrading research and development. Biochar, as an adsorption filter material, has a rich pore structure and excellent adsorption performance, and its raw materials come from a wide range of sources, such as agricultural and forestry waste, animal manure, and so on. At present, most of the research on biochar is based on powdered biochar, but powdered biochar is difficult to recover due to its extremely fine particles, which have limitations in process applications. Attapulgite as a one-dimensional nanorod crystal is an ideal matrix for constructing composite materials. In this study, agricultural and forestry wastes such as rice husk and peanut husk were used as biomass raw materials and attapulgite were fired to produce composite particles with certain shapes and sizes. The mechanism of the influence of pyrolysis temperature, material proportion, particle size and other conditions on the physicochemical properties of composite particle biochar and the adsorption effect of ammonia nitrogen will provide a theoretical basis for the research and development of biochar particle adsorption filter media and its practical application.