On the basis of the investigation of the economic development of the hinterland，the development of the port and the needs of enterprises，the impact of the 12.5 m deep water channel II phase project of the Yangtze River below Nanjing on the development of Jiangyin Port is studied by a research method combining qualitative analysis and quantitative calculation.The analysis concludes：1）The implementation of the 12.5 m deep water channel II phase project has greatly improved the navigation conditions from Nanjing to Nantong section of the Yangtze River and created favorable conditions for CAPE ships to enter Jiangyin Port. 2）The large-scale ships have greatly increased the actual load rate，which have not only enabled Jiangyin Port to achieve a substantial increase in throughput，but also reduced the logistics cost of enterprises. It has promoted the optimization and adjustment of the ship transportation organization，and reduced the pollution and carbon emissions of ships，and promoted the green development of the port.