Abstract: According to the study on the illuvial depth of CaCO₃, CaCO₃ content and leached cracks, it is determined that moving depth of CaCO₃ illuvial horizon represents the permeated depth of gravitative water, and the distance from the top of paleosol to the bottom of CaCO₃ illuvial horizon is the thickness for the permeated zone for gravitative water.The permeated depth of gravitative water can reliably reflect the precipitation and can be used as the basis for determining the depth of film water zone and groundwater level. In general, groundwater can be classified into the gravitative water zone and the film water zone, but the gravitative water may stretch down to the groundwater level and film water zone is lacking in the area with rich rainfall.The precipitation during the development of the paleosols from 1st to 7th layer was between 600 and 1000 mm, with maximum difference less than one time. However the permeated depth for gravitative water of seven layers of paleosol is between 7.4 and 0.7 m, with maximum difference more than ten times, which demonstrates that the rainfall during warm and moist periods of Pleistocene was uneven, rain season and dry season were obvious, that increased rainfall mainly concentrated in rain season, and the difference in rainfall between dry period and moist pertod was great in rain season and little in dry season.