原住民族、土地利用、農業與部落發展具有密切關係，並受到族人土地觀、社會經濟環境與政府政策等諸多內外因素所影響。 　　過去以來，主流社會常將山林環境災害歸諸於高山地區不當的土地利用，導致原住民在高山地區進行農業活動受到諸多法令規章限制。政府近年來致力推廣造林與部落觀光事業，以期防止山林環境惡化、滿足國人休閒需求與將經濟效益引至部落，惟部分舉措因未適切於族人普遍經濟能力、在地就業需求與對部落發展之想望，恐無益部落永續發展。 　　為進一步理解原住民族農地利用與部落發展相關課題，本文提出以下課題：一、高山農地利用是否必然造成環境災害問題？二、影響原住民族農業進行的跨尺度網絡為何？該網絡如何提供部落發展農業與增進土地利用之實質助益？再以新竹縣尖石鄉石磊部落作為研究對象進行實證分析，透過參與式觀察與文獻回顧等研究方法，兼以Leopold土地倫理與Adger跨尺度網絡理論，探討石磊部落族人推展有機與自然農業時之轉型歷程與內涵，並分析各項跨尺度網絡要素的關連性互動。 　　最終，本研究認為，倘原住民族農地利用能兼顧環境保護、經濟效率與社會公平，也能帶給部落具有主體性的發展實益，則外界應毋須再以災難眼光相待，反應思考如何從部落角度，協助原住民族實踐更友善於環境的農地利用，以發揮農地多功能利用之特性，並促使部落朝向兼顧環境及經濟的永續發展。 / There are close associations among tribe developments, indigenous peoples, land-utilization, and agriculture. Many internal and external factors such as indigenous peoples’ intellections of land, social economics environment, and government’s policies influence tribe development as well. 　　For the past few decades, mainstream society usually have attributed forest environmental emergency to inappropriate land utilization in mountain regions and it caused aborigines to be confined by many laws and regulations when undergoing agriculture activities in mountain regions. For the past few years, the government has dedicated to promoting forestation and tribe tourism to avoid worsening of the forest environments as well as to satisfy the leisure demands of country people and to bring economic benefits to the tribes. Nevertheless, parts of initiatives may not help the sustainable development of the tribes since neglecting the average economics ability of indigenous peoples, demands of local employments, and visions of tribe development. 　　To further understand related issues about farmland utilization and tribe development of the indigenous peoples, this research proposed the following issues. The first issue is whether farmland utilization of mountain regions inevitably causes environmental emergency. And the second issue is to analyze what is the cross-scale networks in resource co-management that influence agricultures of indigenous peoples and how this network provides real benefits to tribe development and improvement of land utilization. Then we took Shi-Lei indigenous community of Jienshih Township in Hsinchu County as a case study to undergo empirical analyses. Through research method such as participant observation and literature reviews as well as Leopold’s land ethics theory and Adger’s cross-scale networks in resource co-management theory, we analyzed the transformed experiences and contents of organic and natural agriculture developed by Shi-Lei indigenous people. Also, we analyzed the related interactions of each element in cross-scale networks. 　　Finally, this research supposes that if indigenous peoples’ farmland utilization can well consider in every aspect of environment protection, economics efficiency, society justice, and bringing real development benefits with subjectivity to the tribe, other people should not link the farmland utilization to potential natural disasters. On the contrary, we should stand in the view of tribes to consider how to help indigenous peoples to reach more eco-friendly farmland utilization. By developing more eco-friendly farmland utilization, farmland can display multi-function characteristics to promote tribes’ sustainable development that give consideration to both environment protection and economics.