The viscoplasticity and compressive strength of cement with high erosion performance were studied. The influences of curing temperature and content of ground granulated blast furnace slag (GGBFS) on these performances of the medium heat cement (including high iron and low calcium phase) were also investigated. The results indicate that the medium heat cement with high iron phase can maintain better fluidity and low temperature sensitivity than that of ordinary Portland cement at high temperature. GGBFS can play an important role in improving the fluidity and stability of the slurry, and avoid the cement setting and hardening prematurely at high temperatures. The microstructure analysis shows that a large amount of CH with layer shape appear in the slurry. The amount of this gel layer in the slurry increased as the curing temperature elevated. The layer can make the cement stone structure more denser, so that the compressive strength of samples are enhanced in the later stage. When the medium heat cement contains 40% GGBFS, the system has the best flow performance and stability under high temperature environment, and can be applied to mass concrete with excessive internal temperature.