In order to address a series of safety management issues involved in low-altitude economic development, the technical routes and principles of low-altitude economy as well as the operational experience of implementation plans are summarized, and four universal construction plans for low-altitude security and protection are analyzed, namely the radar and integrated perception technology fusion plan, the broadcast automatic dependent surveillance technology plan, the remote identification technology plan, and the multi-source fusion plan based on TDOA radio technology. On this basis, an evaluation index system for unmanned aerial vehicle detection technology was constructed, and a multi-attribute evaluation method based on DEMATEL and TOPSIS was established. The results show that the multi-source fusion plan based on time difference of arrival (TDOA) is an effective and universal solution for building a low-altitude security system in cities. It is concluded that the construction of a low-altitude security system is a systematic project, which requires the joint efforts of governments, enterprises and the whole society. Integration is needed at the levels of technology, data and operation to meet the future development needs of the low-altitude economy.