The adaptability of physical and chemical properties of cement to liquid setting accelerator is studied; and the mechanism of the adaptability is analyzed by means of scanning electron microscopy(SEM) and Xray diffraction(XRD). The study results indicate that: 1) The adaptability of aluminate liquid accelerator is bad to low C3Acontent cement and low watercontent cement; and the mixing proportion of aluminate liquid accelerator should be greatly increased so as to meet the requirement of setting time. 2) The liquid setting accelerator conditioned by silicate shows better adaptability, while it will lower the early strength of mortar when it is used in low C3Scontent sulfate content.