Abstract: The paper presents the effect of sodium silicate amount on the property of alkali slag cement (ASC) under the condition of thermal excitation. The results shows that two important effects of "thermal excitation" were developed by means of steam curing: (1) when sodium silicate adding amount in the range of 8.89%?18.45%, the time limit of excitation would be shorten to 1/10 of normal curing; (2) when sodium silicate content keeps at >12%~13%, the strength of ASC keeps unchanged and 12h compression strength is over 50Mpa. XRD and SEM analysis shows that the hydration products in alkali slag paste is as same as under normal temperature when having steam curing, which is mainly composing C-S-H, but the crystallinity is low.