Abstract: The Bohai Sea is a semi-enclosed inland sea, and land-based pollution is the main cause of marine environmental pollution in the Bohai Sea. Pollution prevention and control with the ocean itself as the spatial scope is still the method of terminal control. Based on the theory of land-sea coordination and the theory of integrated marine management based on the ecosystem, the spatial scope of the Bohai Sea pollution prevention and control is extended to the rivers entering the sea, and the pollution prevention mechanism of watershed-estuary-coastal waters is established. The implementation of the integrated pollution control strategy on land and sea is conducive to solving the environmental problems in Bohai Sea. The pollution prevention and control mechanism of watershed-estuary-coastal waters can be designed in terms of coordinated management of pollution prevention and control, total control, scientific planning, and ecological compensation.