To scientifically evaluate the economic and social benefits of the 12.5-meter deep-water channel second-phase project below the Yangtze River below Nanjing,we analyze the economic benefit,macro-benefit,social benefit and environment benefit of the project by building a transportation economic model,an input-output model and a gravity model.The research reveals that significant benefits such as reducing logistics costs,driving regional economic growth,adding new jobs,stimulating fiscal revenue growth,and promoting energy conservation.Thus the strategic significance of the project is fully reflected.