scientific and technological revolution and industrial reform are developing in depth，and mankind is entering an era of intelligent interconnection of all things with the ternary integration of “human，machine and things”. The digital transformation of cities is an inevitable process in this digital age，showing the development characteristics of multidimensional interconnection of “human，machine and things”，real-time data circulation，intelligent application stacking，ubiquitous scene integration，and coexistence of online and offline. This means that the Cyberspace boundaries in the urban complex giant systems are becoming increasingly blurred and the vulnerabilities are prominent. The traditional boundary-based cybersecurity protection system cannot follow the development requirements of urban digital transformation. It can be said that the trust relationship and trust mechanism in various economic and social activities that fully rely on digital interaction between people and people，people and things，and things and things need to be reshaped. Therefore，we must build a new digital trust system.

In this context，this report analyzes the new risks and challenges faced by digital trust under the digital transformation of cities，draws on domestic and foreign development experience and practical cases，and builds a digital trust strategy that dynamically matches and organically couples a trusted digital identity system and a data circulation trust system，and put forward countermeasures and suggestions for the construction of digital trust system for digital transformation of relevant cities and practical cases in typical scenarios to help the construction of data market，promote the digitalization of economy，digitalization of life，digitalization of governance，etc.