With the continuous development of technology, the traditional Internet of things has been unable to meet the application of massive equipment, thus NB-IoT emerges. This paper introduces the technical characteristics and system architecture of NB-IoT, points out the security risks in detail, and puts forward the security protection measures. With the continuous development of technol- ogy and the continuous improvement of the Internet of things application ecosystem, NB-IoT is bound to have a profound impact on society.