In order to improve the emergency response ability in the traffic-intensive waters，a brittle node identifi- cation method for navigation system based on different attack strategies was proposed． Firstly，based on the original mapping method，the topological structure of the navigation system in traffic-intensive waters was modeled，and the network topology statistical characteristics of the navigation system were analyzed． Then the brittle node of the sys- tem was identified by analyzing the changes of global network efficiency in traffic-intensive waters under different at- tack strategies． Taking the navigation system of the Yangtze Ｒiver estuary as an example，a case study on the brittle node identification of the traffic flow in traffic-intensive waters was carried out． The research results show that the identification of the brittle nodes of navigation systems in traffic-intensive waters with the complex network method and the analysis of the nodes and brittle nodes of navigation system under different attack strategies can effectively identify the key vulnerabilities that affect the reliability of the ship navigation system． By effectively pre-controlling the identified key nodes and routes，it can help to reduce the vulnerability of the whole navigation system．