A digital twin is developed for the specific purposes in each domain, such as manufacturing, transportation, energy, and safety, which is suitable for providing functions and services for each domain, but requires functional expansion to provide services for smart sustainable cities and communities with multiple domains. Digital twin federation (DTF) is a combination of digital twin systems in various fields. The digital twin federation may face security threats, such as system denial of service, data tampering, DDoS attacks, illegal data sharing, authority upgrading, etc. sending illegal instructions or malicious codes to other digital twin systems through the digital twin federation has seriously affected the security and operation of the digital twin federation. In order to ensure the security of the digital twin federation, the security threats and relevant security requirements specific to digital twin federation need to be analysed and the security measures need to be established. This recommendation identifies the specific security threats of the digital twin federation, analyses security requirements specific to the digital twin federation, and thus establishes the security measures of the digital twin federation.