Emergency needs full information. To transfer it from the disaster area without the ground base station needs a quick and a reliable network. It is a good solution to use emergency mobile Internet of Things (emIoT). This type of IoT is energy efficient and suit for long-distance transmission. Consider UAVs as an air-based communication platform. We researched on the long-distance communication in emIoT with mass mobile energy-constrained devices. An energy saving strategy based on UAVs is proposed. First

model this type of IoT. Second

according to the disorderly scattered ground devices in the stereo disaster area

the strategy optimizes UAVs deployment. It can provide a reliable communication and reduce the energy consumption of the communication at the same time. Third

given the ground equipment moves randomly and widely. A joint motion pattern about UAVs and ground mobile devices was analyzed. It avoids long-distance moving caused by frequent changes of cluster coverage with UAVs and reduces the mobile energy. Finally

from transferring to moving energy-saving

the effect of the proposed strategy is verified through experiments.