Abstract: The urban lifeline safety engineering aims to prevent major safety accidents such as gas explosions, bridge collapses, road surface collapses, and urban waterlogging. Based on the public safety technology and combined with digital technologies such as the internet of things, big data, and cloud computing, it is wished to achieve overall monitoring, dynamic examination, early warning, and efficient response of lifeline engineering. The theoretical system of urban lifeline safety engineering was firstly elaborated, including comprehensive monitoring theory of urban lifeline safety, the platform framework of "sensing, transmitting, knowing, and using", the risk prevention and control mechanism of multi departmental collaborative linkage, and the standard system for urban lifeline monitoring and operation services. Secondly, representative monitoring and early warning technologies in four typical fields, such as urban gas, bridge, water supply, and drainage, were analyzed. Among them, the monitoring and early warning technologies for safety risk of gas mainly include monitoring technologies for the operation status of gas pipelines, leakage monitoring and early warning technologies for adjacent underground spaces of gas pipelines and monitoring and early warning technologies for third-party construction damage of gas pipelines. The monitoring and early warning technologies for safety risk of bridge mainly include early warning technologies for responding to exceeding limits, early warning technologies based on algorithm models, and early warning technologies based on comprehensive experiments. The monitoring and early warning technologies for safety risks of water supply mainly include monitoring and early warning technologies for water supply network leakage, and explosion location and auxiliary impact analysis technologies for water supply network. The monitoring and early warning technologies for safety risks of drainage mainly include monitoring and diagnosis technologies for diseases in drainage pipe network and early warning technologies for urban waterlogging risk. Subsequently, the basic situations and application effectiveness of urban lifeline safety engineering construction in Hefei City and Anhui Province were introduced. As of July 2024, Hefei City has coordinated the disposal of 932 level three or above warning events, and Anhui Province has effectively disposed of 1754 level three or above warning events. Finally, the future development trends were proposed from three perspectives: national major needs, technological equipment innovation, and application scenario expansion. In terms of national major needs, it is necessary to perceive and warn of urban safety risks through urban lifeline safety engineering, ensure people's livelihoods, and achieve independent and controllable basic engineering software and rescue equipment. In terms of technological equipment innovation, it is urgent to carry out research and development in the theory of diagnosis and resilience enhancement, operation monitoring and disaster warning technologies, prevention and control technologies and disposal equipments for urban lifeline safety. In terms of application scenario expansion, the scenarios need to be extended to areas such as thermal pipelines, comprehensive pipe galleries, power facilities, and rail transit, and further technological breakthroughs need to be made to prevent and control existing and emerging risks. The research results can strengthen the understanding and recognition of urban lifeline safety engineering, and assist in the comprehensive promotion of urban lifeline safety engineering in China.