In order to study the features of Mountainous watershed runoff and erosion in karst region, , on the basis of design of experiment of the the big pore, slope runoff and erosion, artificial rainfall runoff experiment is made, by establishing artificial rainfall, slope runoff test plot. Large quantities of data were obtained through the artificial rainfall test. According to the experimental data, under different rainfall intensity, rainfall, under the pad surface and rainfall process, regularity of slope runoff and sediment yield in karst area is studied to provide data validation for the development of slope runoff and sediment yield model in karst region.