Chemical composition, microstructure and morphologic feature of phosphorus slag powder, the effects of phosphorus slag powder and fly ash as admixtures on hydration heat and strength of cementitious materials, and mechanics, thermology, deformation and durability performances of hydraulic concrete were completely researched and analyzed. The results show that: phosphorus slag powder can reduce adiabatic temperature rise of concrete, which is beneficial to the construction, temperature control and anti-crack of mass concrete ； compared with concrete mixed with fly ash, concrete mixed with phosphorus slag powder has a higher strength growing rate in late age, and higher ultimate tension ； phosphorus slag powder has no adverse effect on the performances of impermeability and frost resistance of concrete. Phosphorus slag powder can replace fly ash partially or completely for application in quantity in concrete.