Abstract: In order to address the issue of the impact of Phosphorus slag incorporation on the strength of cement, this article prepared cement-based cementitious materials with different amounts of phosphorus slag powder, and compared the hydration and mechanical properties of phosphorus slag cement composite cementitious materials at different curing temperatures. The influences of phosphorus slag powder on the workability, hydration products and characteristics, and mechanical properties of cement at different curing temperatures were evaluated through standard consistency, X-ray diffraction(XRD)analysis, hydration temperature rise analysis and compressive strength of the mortar. The results showed that as the curing temperature increased, the retarding effect brought by the addition of phosphorus slag powder was weakened, and the relative activity index of phosphorus slag cement composite cementitious materials at 7 days and 28 days increased significantly. When the curing temperature increased from 20 ℃ to 40 ℃, the relative activity index of phosphorus slag admixture increased from 88% to 115% at 28 days. Moreover, with the increase of phosphorus slag content, the effect of curing temperature on its performance became more significant.