Taking the Donggou watershed as a small representative watershed for the mountainous area and using the integrated benefit method and the comprehensive function method,ecosystem of the small watershed is evaluated for the integrated benefits and comprehensive functions before and after soil erosion programs are implemented.Analyses indicate that the used methods can describe the single benefit and integrated benefit resulted from the projects of soil and water conservation and ecological construction in small watersheds,and are suitable to ecological economic system appraisal in the complex eroded mountainous area.