The Chinese coastal ecosystem, a vital zone of ecological and economic significance, faces escalating pressures under climate change and human activities. This study examines the ecological dynamics of China's coastal regions, emphasizing the interaction between climate-driven stressors and anthropogenic activities. Heat waves, ocean acidification, hypoxia and imbalance of nutrients have exacerbated ecological disasters, including harmful algal blooms (red tides), large-scale green algae (e.g., Ulva prolifera) bloom, and jellyfish blooms, which disrupt biodiversity, fisheries, and coastal livelihoods. Concurrently, the rapid expansion of aquaculture has strained ecological carrying capacity, with overexploitation of resources and nutrient pollution further degrading water quality and habitat integrity. We will evaluate the ecological capacity and healthy condition of key coastal zones, revealing declining resilience due to combination of climate impacts and unsustainable practices. Case studies highlight regions such as the Bohai Sea, Yellow Sea, and East China Sea, where eutrophication and hypoxia threaten marine ecosystems and aquaculture productivity. Mitigation strategies, including integrated coastal zone management, nutrient load reduction, and climate-adaptive aquaculture practices, are proposed to enhance sustainability. By synthesizing climatic, ecological, and socioeconomic data, this study underscores the urgency of balancing economic development with ecological preservation to safeguard China's coastal ecosystems in a warming world.