Under global climate change, how to adapt climate change and tackle ecological problem is becoming an urgent issue for agricultural production over the world. As a key factor for sustainable development of regional agriculture and ecosystem, carrying out studies on agricultural structural adjustment and adaptive measures are very important for decreasing the adverse impacts of climate change. Transforming the existing production type of wood and sheep husbandry which mainly depending on mountains to oasis in Manas River Basin is considered as the wise alternative of resolving environment problem caused by overgrazing in mountains. However, water resource must be the limitation when finishing the transforming and agricultural structure adjustment in oasis. So this paper sets up several Scenario Analysis in achieving the function converting. The results show that it is feasible that developing forest and animal husbandry by establishing high productive and fast-growing forests and intensive grassland in oasis to protect the mountains and deserts in order to make them playing great ecosystem service function.