The general form of the North-branch of the Changjiang River mouth has changed greatly due to the change of the main stream lines of the Nantong reach of the Changjiang River and the influence of human activities. By the 1930s,the main stream lines of the Nantong reach of the Changjiang River has shifted to the Tongzhousha west channel.The North-branch at the Changjiang River mouth has become atrophic because of Tongzhousha east channel’s deposition.After 1958,Tonghaisha and Jiangxinsha were exploited.And in 1970 the North-branch of Jiangxinsha was blocked up.All these things make the water of the North-branch more difficult to pass through.It leads to the decline of the total discharge percentage of the North-branch.And it causes the rising-tide to go back to the South-branch.However, since 1978,with the development of Tongzhousha east channel and its left bank being scoured,the water amount of entering the North-branch is increasing.And the water, load and salt of going back to the South-branch is becoming less.A series of plans to regulate and exploit the North-branch have been put forward but each one has its weakpoint except the plan of making the river channel at Lianxingang narrow,It can prevent the water,load and salt from going back to the South-branch.And at the same time it can also keep up the normal natural and social environment.Undoubtedly,it is the best way to regulate and exploit the North-branch.