Abstract: Phosphogypsum (PG) is an acidic by-product produced during the production of phosphoric acid from phosphate rock. In China, only 25% of PG is recycled at present, while 75% is stored by wet storage method in valley regions due to restriction of terrain and economic consideration. Based on the Liushuqing PG stacking dam, the physical properties of deposition PG including density, moisture content, infiltration, soil water characteristics and grade are tested. The mechanical properties of triaxial CU, creep and dynamic triaxial tests are performed. The results show that: (1) The dry density and depth are not related; (2) The deposition PG does not have a natural graded phenomenon, but it has significant anisotropy; (3) The deposition PG has a high friction angle and liquefaction resistance, but its creep deformation is great and seepage gradient is small. The above work provides the basis for the stability analysis of PG stacking dam, and it has an important meaning to the operation management of the existing project and the design of new projects.