[Objective]Returning farmland to forest and mountain enclosure for grazing prohibition ecological effect and economy rationality were explored.[Methods]A case study of returning farmland to forest and barren hills grazing prohibition in Yongxing Township of Jingyuan County was used to discuss and estimate the relative ecological function and relative ecological value.[Results]1)The ecological value of the forest of returning farmland was far more than the sum of the ecological value of farm crops and the agricultural output,and also more than the national subsidy standard.So the state policy of returning farmland to forests is not only favorable to local eco-environment restoration,but also reasonable in economic development.2)The ecological value of mountain enclosure for grazing prohibition was less than the opportunity cost of prohibiting grazing,also less than the national subsidy standard.The sum of the relative ecological value of prohibiting grazing and the state subsidies was more than the opportunity cost of prohibiting grazing.However,the ecological value of new vegetation through returning farmland to forest project was greater than the China’s average ecological value of grassland.[Conclusion]The relative ecological value can be used to solve the problems in the equivalent conversion among various ecological indexes and between ecological indexes and economic indexes. [Objective] Returning farmland to forest and mountain enclosure for grazing prohibition ecological effect and economy rationality were explored. [Methods] A case study of returning farmland to forest and barren hills grazing prohibition in Yongxing Township of Jingyuan County was used to discuss and estimate the [Results] 1) The ecological value of the forest of returning farmland was far more than the sum of the ecological value of farm crops and the agricultural output, and also more than the national subsidy standard. the state policy of returning farmland to forests is not only favorable to local eco-environment restoration, but also reasonable in economic development.2) The ecological value of mountain enclosure for grazing prohibition was less than the opportunity cost of prohibiting grazing, also less than than the national subsidy standard. The sum of the relative ecological value of prohibiting grazing and the state subsidies was m ore than the opportunity cost of prohibiting grazing.However, the ecological value of new vegetation through returning farmland to forest project was greater than the China’s average ecological value of grassland. [Conclusion] The relative ecological value can be used to solve the problems in the the equivalent conversion among various ecological indexes and between ecological indexes and economic indexes.