Abstract: With the continuous progress of urbanization in China, the scale of urban population and infrastructure is growing, various risks are accumulated, disasters and accidents occur frequently, and urban public security has become an increasingly prominent issue. Nondestructive testing technology can monitor the safety of various disaster carriers without destroying their basic structure, so it is widely used in the field of urban public security. This paper briefly introduces the concept, methods and development of NDT technology, and describes in detail the application of various kinds of NDT methods in the assessment and monitoring of public security emergencies such as accidents, disasters and natural hazards. Finally, combined with the development requirements of urban public security and the promotion of new technologies such as the internet of things and big data, the future development direction of NDT technology is prospected.