Abstract: Digital twin water conservancy project is an important milestone of the applications of digital twin watershed, and an important part of smart water conservancy construction.Therefore, how to ensure the network security is particularly important in the construction of digital twin water conservancy project.Taking the construction of digital twin project in Hanjiang River Basin as an example and combining with the characteristics of digital twin water conservancy projects, we analyze the network security risks faced by digital twin water conservancy projects.On this basis, we build a digital twin water conservancy project network security technology risk management system, which are built from six aspects: network security in-depth defense system construction, Internet of Things security protection, data security protection, water conservancy industry control system security protection, cloud computing security protection, and mobile security protection.Concrete measures and suggestions are put forward for the network security management of digital twin water conservancy projects in water conservancy industry.The results have been successfully applied to the Hanjiang River Basin water scheduling and management in 2022,and achieving satisfied protection effect, which can provide references for network security work in other digital twin project in other industries.