Background The evaluation of ecological clean small watersheds is not only an important way to verify the development results of ecological clean small watersheds, but also an effective way to improve the development model of ecological clean small watersheds. In this study, the evaluation index system of ecological clean small watersheds in Hainan province was established to provide a scientific basis for the comprehensive management of small watersheds in Hainan province and the improvement of governance models.

Methods According to the principal for selection and establishment of the index system, the evaluation index system framework of ecological clean small watershed was developed based on the analytic hierarchy process. The index system consists of three levels: Target, criterion and indicator layer, including three parts of ecology, production, and life. The 16 evaluation indicators based on Technical Specification for Ecological Clean Small Watershed Construction (SL/T 534-2023) were selected as the basis for the evaluation system of ecological clean small watershed in Hainan province. Considering the current situation of ecological clean small watershed management in Hainan province, the specific contents of some indicators were refined, and the grading standards of each indicator were determined, and the scores were assigned item by item also. Wenbai Ecological Clean Small Watershed in Danzhou city was used an example to evaluate the level before and after the construction.

Results Before the governance, score for ecology, production and life indicators of Wenbai Ecological Clean Small Watershed were 2.097, 0.408 and 7.218 respectively, especially for the indictors of ecology and life. The comprehensive score was only 3.133, which did not meet the requirements of ecological clean small watershed. After the governance of ecological clean small watershed construction, all indictors of ecology and life significantly raised. The scores for ecology, production and life increased to 6.517, 4.325 and 10.000, respectively. The comprehensive score increased to 6.909, and the level reached two-star. The small watershed ecosystem was in the progress for positive, coordinated and stable development. As the production indicators were still at a relative low level, the development of advantageous industries such as tourism need to be emphasized to promote the development of rural economy and increase the income of residents in the future.

Conclusions The evaluation index system can be used to assess the benefit of small watershed construction and to provide a reference for the steady development for further ecological civilization construction with high quality in Hainan province.