Abstract: Soil erosion being an important earth surface process,its environmental impact has aroused wide attention globally world over.From the angle of its influencing factors and basic principles of the generation of its environmental effects,the processes of soil water erosion were analyzed,leading to the assumption that soil water erosion is a "passive" or "secondary" process,which is affected and restrained by natural factors and human activities.The initiation and development of soil water erosion process will also act on local and allopatric environmental systems,demonstrating a series of environmental effects.The researches oriented towards environmental effects of soil water erosion are focused mainly on effects of soil water erosion on soil quality,plant productivity and vegetation restoration,non-point source pollution risk,carbon cycling and global change.An index system for evaluation of environmental effects of soil water erosion can be established and formed of four major aspects,i.e.water,soil,atmosphere and biology.It is,however,very difficult to formulate a standardized index system adoptable to all geographic environmental conditions and scenarios due to variability of research objectives and intrinsic spatial differentiation of the earth surface.In contrast,the modular formulation approach,which integrates basic indices with optional ones,is more operable.Specific indices and approaches to acquisition and analysis of their data are all scale dependent.

Key words: soil erosion, index system, environmental impact, scale