Abstract: Tianjin, a city located at the lowest reaches of the Haihe river basin and close to the bottom of the Bohai Bay, which is the confluence and estuary of the five major tributaries of the Haihe river basin. For a long time, the water quality of the coastal waters has been inferior to Class IV, the rivers entering the sea have been inferior to Class V, and the compliance rate of pollution sources directly discharged to the sea is relatively low. After the implementation of the tough battle of Bohai comprehensive governance, the proportion of areas with good water quality (Class I and Class II) in Tianjin’s coastal waters reached 70.4%, exceeding the target value of 16% by 54.4 percentage points, and all 8 rivers entering the sea have been eliminated inferior in 2020. Pollution sources directly discharged to the sea achieved stable and up-to-standard emission since July 2019. This paper sorts out the key countermeasures for land pollution control, from the aspects of pollution control of industrial enterprises, urban life, agriculture and rural areas, and comprehensive improvement of pollution sources directly discharged to the sea and the rivers entering the sea, revealing the qualitative change process of water quality improvement in coastal waters, and condenses the governance experience of “source governance, channel management and control” provides a reference for consolidating and enhancing the effectiveness of the battle of Bohai comprehensive governance, and in-depth fighting the tough battle for the comprehensive governance of key sea areas.