By comparing the laboratory and field sediment yield on the slope of 25 degree under the artificial rain,the results show that: when rainfall intensity are same or close,laboratory and field rainfall erosivity are extremely close and soil erodibility differs from 4 times;when the other factors like soil bulk density,soil moisture content are same or close and if the accululated sediment yields similarity is only got,the scale of the field model is two times of the laboratory model.The absolate error of the accumulated sidement yields is less than 10 percent;The process of the laboratory sediment yeild of erosion differs from the field very much based on sediment yield rate of erosion;Under the laboratory and the field experiment,the rills on the slope are more when the rainfall intensity is bigger.And the average length,width,depth of the rills are all bigger.But there are many difficulties in the laboratory and field experimental similarity to the slope shape growth.