A leading industry in a region refers to an industry that can drive industrial development and economic growth in the region. It is generally selected subject to qualitative and quantitative analysis. This paper uses Poyang Lake Eco-economic Zone as an example to propose modern agriculture, new industry, and eco-tourism as leading industries for Poyang Lake Eco-economic Zone based on the historical study in compliance with the following aspects: theories and principles of selecting a regionally leading industry; indicators such as comparative advantages, industry associations, regionally economic promotion, industrial development potential, technological improvement, and social benefits; AHP method as the key method; development trend of Poyang Lake Ecological Economic Zone; qualitative and quantitative selection of leading industries for Poyang Lake Eco-economic Zone.