Abstract: The water absorption characteristics of rocks are closely related to the temperature and humidity of environment.The rainfall type slopes with rock as the main material are always formed in a certain temperature and humidity environment.It is one-side to study the sliding disaster mechanism of rock water absorption solely.By using the intelligent testing system for vapor water absorption of soft rock and simulating rainfall temperature and humid environment to study the relationship between rock water absorption and three factors such as lithology,rain delay and temperature,it is concluded that the lithological composition is different and the hydraulic response characteristics of the rainfall type rock slope are also different.It indicates that in the rainfall＇s temperature and humidity(20℃,100%),dry conglomerate＇s water absorption is biggest,and sandstone is second while epidotic amphibolite is minimal.The conglomerate has strong rain infiltration capacity,and sandstone＇s curve slope is negative when the water absorption reaches peak.It shows that absorption rule changes from absorption to ponding.Epidotic amphibolite soon present “condensation” phenomenon,and its infiltration capacity is very weak.The research reveals that rock slope whose main component is conglomerate has strong ability of rain infiltration.During heavy rainfall,the effect of seepage and underground runoff is the main factor.It is necessary to consider the coupling effect of seepage and runoff.Rock slope whose main component is epidotic amphibolite has strong ability of drainage.During heavy rainfall,the effect of surface runoff and underground runoff is the main factor,so it is necessary to considers groundwater seepage force as the main factor.