Abstract: The ocean is of great significance to humanity. It not only regulates the global climate, but it also plays a vital role in providing food, livelihood, and entertainment. The 18th National Congress of the Communist Party of China proposed:improving the capabilityfor marine resource exploration, developing the marine economy, protecting the marine ecological environment, firmly safeguarding the rights and interests of the nation's seas, and building a strong maritime nation. As one of the world's mega coastal cities, Shanghai must understand the changing trends and status of its ocean ecosystem health,and the interaction between cities and oceans. The current challenges for Shanghai's ocean coast are marine pollution, land reclamation, and typhoon storms caused by global changes. Based on evaluation methods for ocean ecosystem health, both in China and abroad, this paper compares two different evaluation methods:the Ocean Health Index (OHI) and the Pressure-State-Response (PSR). The paper evaluates the changing trends and status of Shanghai's ocean ecosystem health. The evaluation results of the two methods show that Shanghai's ocean ecosystem became healthier since 2009; it was, however,foundto be in a state of sub-standard health in 2015. The "Pressure-State-Response" (PSR) model, moreover, was found to be most suitable for Shanghai. This study provides scientific advice for the development of land and sea in Shanghai, as well as research cases for other coastal cities.

Key words: Ocean Health Index, Pressure-State-Response model, marine ecosystem health, Shanghai