[Objective] The ecological benefit of returning farmland to forestry projects in Danzhou City, Hainan Pvovince was to evaluated in order to provide a basis for eco-benefit assessment of returning farmland to forestland project in China. [Methods] Based on the achievements of returning farmland to forestland project in Danzhou City that finished in 2012, the following six aspects of the water conservation, soil and water conservation, carbon sequestration oxygen, purifying environment, improving the microclimate and protecting the biodiversity of Danzhou City project on returning farmland to forest vegetation were evaluated. The shadow engineering method and the market price method were used to carry on the physical and value assessment, analyze the forest ecological benefit of returning farmland in nearly nine years, and combine the Engel coefficient with the Pearson curve together to modify the evaluation results. [Results] By 2012, the ecological value of returning farmland to forestland project of Danzhou City was up to 2.22 billion yuan. The most important value is protection of water resources, 1.76 billion yuan, accounting for 79.5% of total ecological value. The following is carbon sequestration oxygen, 238 million yuan, accounting for 10.7% of total ecological value. [Conclusion] The ecological benefit brought by the implementation of returning farmland to forestland project of Danzhou City is very significant, and effectively control soil and water loss in Danzhou City.