This dissertation has discussed the ecological process of the surface water of Inner Mongolia typical steppe and influencing factor by means of the method,which contains both the determination of runoff in field and simulated runoff in field and simulated runoff in the laboratory,here we present several key findings:First,the vegetation degradation is the primary factor causing fluctuations in surface runoff.A significant positive correlation was found between surface runoff and degradation intensity.The vegetation degradation both increased obviously with the surface runoff coefficient and runoff discharge.Second,the plant height and density of vegetation canopy is the primary factor causing fluctuations in surface runoff.The surface runoff coefficient and the surface runoff discharge decreases gradually along the plant height and density.However,the influence of plant height were higher than the influence of plant density on surface runoff at an certain condition.Third,the influence of litter on surface runoff was very serious,it was mainly influenced by directly interception effect and indirectly barrier effect.The influence of litter were higher than the influence of vegetation on surface runoff at an certain condition.