Abstract: Coastal wetlands are mainly waters with a depth of less than 6 meters during low tide and their coastal wetted areas. It includes permanent waters, Intertidal zone and coastal low-lying areas with a water depth of no more than 6m. Wetlands have values such as flow regulation, preventing seawater intrusion, supplementing groundwater or sedimentation of nutrients from groundwater, regulating climate, maintaining biodiversity and ecological functions, protecting coasts, tourism development, education and scientific research. The global coastal wetland area is approximately 1.42 million km². With the rapid population growth, socio-economic development, industrialization, and urbanization process in coastal areas, the global coastal wetland ecosystem is severely degraded, seriously restricting the harmonious coexistence of humans and nature. It is urgent to implement comprehensive and systematic protection of global coastal wetlands. This article summarizes the technological progress of coastal ecological restoration and environmental optimization both domestically and internationally, and analyzes the achievements and cases at home and abroad. It summarizes the characteristics and advantages of China's coastal wetland ecological restoration technology, especially the new achievements made since the implementation of the Beautiful China Ecological Civilization Project, which has important reference significance and demonstration role for coastal ecological restoration and environmental optimization, propose suggestions and promotion measures for ecological restoration and environmental optimization of the China's coastal zones, to assist in the construction of national “Carbon Peaking and Carbon Neutrality” strategy, national marine ecological civilization and sustainable development of marine economy.

Key words: Coastal wetlands, ecological restoration, environmental optimization, opportunities and challenges