Abstract: In order to study the mechanisms of water glass to strengthening clayey rock, clay samples were soaked in 50g/L water glass solution for 6h at 80℃,then separated, oven dried, and analyzed through FTIR , XRD and XPS .The changes of whole chemical constitutions of the clays are too small to be indicated by IR spectroscopy. The results of XRD and XPS showed that there are surface reactions between clay minerals and water glass, which may increase the adhesion forces among clay particles.