In order to establish a scientific and feasible evaluation standard for ecological clean integrity of small watershed which can provide reliable technical support for the construction of ecological clean small watershed，soil condition，ecosystem，water environment，human society and economic development were taken into account in this paper，the evaluation index and grading standard of ecological sanitation in small watershed were put forward，small watershed in Jiangxi province Ganxian Jiantian was used as an example.The evaluation results were in line with the actual situation of the river basin，the 14 key indicators proposed cound reveal the overall situation of ecological clean in small watershed，the evaluation method was scientific and feasible，the ecological cleanliness of Jiantian was 7.82 which rating was classified as “general” and near “clean”. Key words：Small watershed management；Ecological cleaning assessment；Analytic hierarchy process；Classification standard