An indicator system was proposed for dynamic assessment of soil anti-erodibility by water (SAEW).A typical small watershed,Zhifanggou in Loess Hilly-gully region,was selected as a study area where dynamic change process of the SAEW was assessed in the period of 1938 to 2000. Relative SAEW index (RSAEWI) together with the concepts of ecosystem health and carrying ability were introduced to evaluate the variation degree of the SAEW,taking the SAEW in 1938 as a benchmark representing the natural conditions.Moreover,the change of the ecosystem health states and resilience characteristics was analyzed.The results showed the SAEW of Zhifanggou Watershed was in the natural state in 1938,since then,because of the human actives’ interferences,the SAEW became lower with high velocity.The trend changed in 1961,when the SAEW reached its lowest level.The SAEW began to recover around 1963,but the recovery speed was relatively slow,and the SAEW failed to meet its natural level after 39 years’ recovery.The SAEW was an important aspect of ecosystem,with the conception of ecosystem health and carrying ability,the SAEW index was graded according to the different health states of ecosystem.In the aspect of SAEW,the ecosystem of Zhifanggou watershed was in a health state during the period of 1938 to 1947,then turned to be subhealth.The health state became better since 1963,and became healthy again in 1990.Based on the analysis of the land-use structure and the recovery characteristics,the curves of R-SAEWI and relative land use structure index (R-SI) revealed the responding relationship beteew SAEWI and land use structure,which proved that the human activity had strong impacts on SAEW.Meanwhile,the time lag appeared in the response curve was discussed.The assessment results agree quite well with those reported by previous investigators,which showed that the method presented in this paper is of primary use for the SAEW prediction and the practice of soil and water conservation.