Belite sulfoaluminate cement was prepared by the segmental calcination system using phosphogypsum (PG) reduced with sulfur gas as the only calcium source. The mineral phase composition and hydration properties were studied by XRD, FT-IR and other analysis methods, and the optimum calcining parameters of cement clinker were determined. The main mineral phases of the clinker are C4A3S?, C2S, and C4AF, with small amounts of C2AS and alpha'- C2S present. As the calcination temperature and calcination time are increased, the content of C4A3S? increases. However, above 1300 °C and 90 min, the formation of C4A3S? is adversely affected. Excessive calcination will reduce the strength of the clinker at each age, which is disadvantageous for its early strength development and is beneficial to its later strength development.