Based on the view of global change and land ocean interaction in the coast zone, the Huanghe River basin,the Huanghe River,its estuary and the Bohai Sea (main in the southern part) form of a large ecosystem, in which they have a close relation with each other. We call it the Huanghe river-Bohai Sea ecosystem. In this large ecosystem, atmospheric circulation and some astronomy factors cause changes on climate in the Huanghe River basin; climate and geomorphologic characteristics and human activities control the fluxes of water and sand and nutrients emptied to the sea. After entering into the sea, these matters are transported by the Bohai and Huanghai Sea’s circulation system and form fishing fields with high production in suitable areas. In addition, many marine dynamic factors changed coastal form and submarine relief, and even impacted the climate and geomorphologic characteristics in the Huanghe basin through atmospheric circulation. There are many factors in this large ecosystem, one of whose change will lead to the changes of others and even result in destroy of all ecosystems. Therefore,   the influence of all factors on marine ecological environment in the   harness and plan in the river basin, or in the river main course and in its estuary should be fully considered. Meanwhile,  the fluxes of water, sand and nutrients emptied to the sea in the protection of marine ecological environment and in their recovery processes should be controlled scientifically. In this large ecosystem, if the two parts of land and ocean contact closely and promote each other, the ecosystem will develop continuously along favorable circle. 