Abstract: In this paper, a nuclear radiation dosimeter based on Nb-Iot（narrow band Internet of things） technology is proposed, which uses STM32F103 series MCU as the main control chip,G-M counter as the radiation dose detector, and integrates temperature and humidity acquisition module. The collected data is sent to OneNet cloud platform through BC20 IOT module. The cloud platform monitors the radiation dose value, temperature and humidity value of the instrument in real time, and displays the Beidou positioning information of the instrument. The radiation dosimeter can realize remote real-time monitoring and positioning, and has the characteristics of lightweight, low power consumption, low cost and wide coverage.