以鄂南花岗岩红壤为研究对象，采用人工降雨试验与调查观测相结合的方法，研究了表土（０～２ｃｍ）的形态和颗粒组成，降雨过程中的变化过程及其对坡面侵蚀的影响。结果表明：１）花岗岩红壤稳定的表土是一上部多砾石，下部较紧密的紧实层。２）紧实层是耕作层表面在降雨过程中经历结皮、压实、粗化几个过程后形成的。３）紧实层的存在影响地表入渗和坡面产流产沙量。 Taking the red soil of granite in the southern part of Hubei Province as the research object, the morphological and the particle composition of topsoil (0 ~ 2cm), the change process during the rainfall and its influence on the slope erosion were studied by combining the artificial rainfall test with the survey observation. The results show that: 1) The topsoil with stable granite red soil is a compacted layer of upper gravel and lower compaction. 2) The compaction layer is formed after the surface of the plow surface undergoes several processes of crusting, compaction and coarsening during rainfall. 3) The existence of compacted layer affects surface infiltration and runoff yield on the slope.