Baed on the thoughts of System science and the grey system theory,the grey systematic characteristics ofcomprehensive control of watershed were analysed in this paper,and the index system and the method of grey systematic appraisal for appraising the benefits of comprehensive management of soil and water conservation were setupas well,On this basis ,the benefits of five watersheds in severe soil loss area of loess plateau were comprehensivelyappraised and analysed which provides a new way for analysis and appraisal of soil and water conservation benefits.