Abstract: It takes loess slope as research object, establishes soil erosion assessment and prediction model, through indoor runoff scour simulation test, studies the change rule of water depth and velocity of slope runoff, and also analyzes the slope runoff hydrodynamic factor’s influence on the slope surface erosion amount.The research result shows that:In the process of soil erosion, with a diversity of time and space distribution characteristics, the change of water depth and velocity of slope runoff is extremely complex. But on the whole, it increases with the increase of runoff scouring flow.Through the analysis of slope surface erosion amount and water erosion of slope factor correlation, multiple regression equation of slope erosion model is established.