Abstract: Atmospheric precipitation flows into catchment soil surface after the interception of vegetations,and would be distributed and transformed at the atmosphere-soil interface.Some of them infiltrate into soil,some of them would be evaporated at soil surface and the other would flow together along the slope to form surface runoff.For a rainfall event that is usually short,water vapor content is close to saturation at ground surface;therefore evaporation at soil surface could be neglected.In this paper,observation data on rainfall infiltration of 118 stations on 7-9 Feb,2009 in Henan Province were analyzed.Soil water content before and after rainfall was measured respectively,and the changes of soil water content in soil layers were determined.Then,the depth of rainfall infiltration was derived according to the changes of soil water content.By the two series of rainfall and infiltration depth data,the relationships between them were established.And the relationships were used to calculate infiltrated water volume in the research area.In addition,infiltration process and depth were also analyzed.Results could provide scientific basis for the analysis of wet soil depth,agricultural production,and prediction of flood control and drought relief.

Key words: Rainfall, Penetration, Penetration depth