Cement-based material has different spalling and physical properties after exposing to different high temperatures. The spalling and physical properties of cement-based material with different additives after exposing to instantaneous high temperature were analyzed. The results show that: all samples have no spalling both at 100℃ and 300℃, but spalling completely at 600℃. The compressive strength and flexural strength of the cement-based material at 100℃ decrease by the rate of 15% and 30%, and the value at 300℃ is close to that at room temperature and decreases rapidly after exposing to 600℃. Both the compressive and the flexural strength of samples with 20% slag powder and 10% silica fume increase with the increase of the temperature when the temperature is below 300℃. SEM reflects that after exposing to 600℃ for 2 hours, C-S-H has changed into a looser structure, and the continuously cement paste is separated into segments.