Abstract: Shanghai is located near the river and the sea, and is highly susceptible to marine disasters such as storm lakes. Designating key defense zones for storm surge disasters is one of the important means to improve the risk management level of storm surge disasters in coastal areas. Based on the risk assessment results of storm surge disasters in Shanghai, this study comprehensively considers historical disaster situations, economy and population, distribution of disaster bearing bodies, and disaster risk assessment information. Taking Chongming District as a pilot, a comprehensive evaluation index system for the delineation of key defense areas in the land area was constructed from the perspectives of disasters, coastal protection engineering, and disaster bearing bodies. From the technical requirements and processes of delineation, suitable methods for the selection, tracing, delineation, and correction of key defense areas for storm surge disasters in Shanghai were proposed, providing reference for the delineation of key defense areas for storm surge disasters in Shanghai.