[Background] The national key project has been implemented in the fifth period( 2013—2017),taking up a lot of financial,material resources and manpower,however,the investigation and research about the control effects of the national key project on soil erosion were not conducted yet.Therefore,the study of the control effect of the national key project of soil and water conservation on soilerosion in the two project regions may provide the reference for understanding and evaluation of the national key projec...