The cutting down and sidewards erosion action of runoff from ground catchment of village system in small watershed，is one of the important causes which result in the extending of gully head and the breaking of topography in loess Yuan region. It is also the major factors which influence the residential safety of village people. On the basis of field investigation，location ob-servation and artifical rainfall in field，the characteristics of runoff and sediment generation on stiff and soft ground were analyzed，thus, a series of vational measures were advanced