The supersulfated cement (SSC) with different content of calcined phosphogypsum (CPG), ground granulated blast-furnace slag and slaked lime was prepared in this study. The effect of CPG content on the hydration properties of SSC was investigated by testing the variation of hydration heat, electrical resistivity, chemical shrinkage, hydration products, pore solution pH value, and compressive strength of cement slurry. The results show that the third peak of heat release curves of cement slurry delays when the CPG content increases from 0% (mass fraction, the same below) to 20% . The cumulative heat at 3 d and the chemical shrinkage at 14 d increase with the increase of CPG. However, the electrical resistivity at 3 d decreases with the increase of CPG, and the pore solution pH value decreases from 11.95 to 10.80. The incorporation of CPG promotes the formation of ettringite. When CPG content is 10%, the 28 d compressive strength of specimen reaches the maximum of 23.8 MPa.