Calcium Silicate Hydrate compounds were synthesized by the reaction of lime and fumed silica.Different reaction conditions with varied temperature, Ca/Si ratio and reaction time were briefly conducted with the product morphology characterized under SEM.In terms of temperature effect, the crystallinity at high temperature exhibited excellent but poor at low temperature.By changing the C/S ratio, the product obtained performed analogous under low temperature while diverse compounds were gained when the temperature was kept high.Moreover, the reaction time required differed too much as well.Under high temperature circumstance,short duration of reaction was sufficient for the good-quality crystal product produced.However, only poor-crystallined product could be formed even prolonged time of the reaction were conducted.Under SEM,good and poor crystallined product was distinguished and characterized.