Preparing phosphogypsum for building materials is an effective way to consume phosphogypsum on a large scale. However, direct incorporation of phosphogypsum in powder form poses a risk of non-point source contamination. Therefore, the paper proposed to prepare pressed particles with phosphogypsum as the main raw material. Meanwhile, cement was used as the cementitious material, and the filling samples were prepared by adding these particles, then the tests such as compressive strength, determination of phosphorus (fluorine) pollutants, pore structure analysis, and microscopic morphological analysis were carried out to verify the filling effect of these particles. The results show that the strength performance of particles-filled samples is better than that of powders-filled samples, and their phosphorus (fluorine) fixation effect is also superior, after soaking for 90 days, the fluoride concentration in the leaching solution of particles-filled samples is 0.035 mg/L, and the phosphorus concentration is 0.35 mg/L, both of which meet the first-level emission standards, and the excellent performance of particles-filled samples is explained by pore structure analysis and microscopic morphological analysis. This research has successfully verified that phosphogypsum has a good filling effect when filled with building materials in the form of particles.