Abstract: There are many children lost in China every year, once child lost, the chance of getting back is very little. Based on this, the design of the childrens anti-lost system based on narrow band Internet of Things (NB-IoT), adopts NB-IoT insteading of traditional Bluetooth, WiFi and GPRS, has the advantages of low power consumption, wide coverage, strong penetration, good signal etc. Using Beidou positioning module to replace the traditional GPS has the advantages of no blind spot and accurate positioning. Using NB-IoT to establish a connection with the base station, the positioning information output by Beidou satellite navigation system is transmitted to the base station through NB-IoT. Users can view the location information of children at any time through the mobile client to help parents quickly locate and retrieve children and reduce the chance of child loss.

Key words: NB-IoT, anti-lost, positioning