<p>Phosphogypsum (PG) poses potential risks to society and the environment. Anhydrite (AH) powder produced from PG is known as phospho-anhydrite powder (PAP). The potential applications of AH remain to be explored. In this study, phospho-anhydrite cement (PAC) was developed using PAP (50–85%), ground granulated blast furnace slag (GGBS, 10–45%) and Portland cement (PC, 5–40%), achieving a maximum compressive strength of over 40&#xa0;MPa. A relationship equation between raw material proportions and 28d compressive strength was established. The content of water-soluble P and F meets the requirements of GB 8978–1996, making the product suitable for use. Through methods such as XRD, Rietveld refinement and chemical analysis of ettringite, it was confirmed that the main hydration products are gypsum and ettringite, and that there is a strong correlation between ettringite content and compressive strength (R² = 0.98). It was also proposed that strength development can be predicted by measuring the heat of hydration. Based on these data, the concept of a fully solid waste anhydrite cement was proposed: provided that the materials can supply sufficient active Al₂O₃ and CaO, an anhydrite cement system with ettringite as the primary hydration product can be established. This was preliminarily verified using steel slag powder and low-grade quicklime. The research of PAC not only expands the avenues for the resource utilisation of PG but also broadens the application fields of anhydrite, providing a viable direction for the development of the phosphorous chemical and gypsum industries.</p>