Abstract: After a major nuclear accident occurs in a nuclear facility, it is of great significance to quickly enter the accident area to obtain the radiation distribution of the site of nuclear leakage and radioactive contamination. In order to overcome the traditional nuclear emergency monitoring methods, which are prone to radiation damage to personnel, poor mobility and low efficiency, this paper designs and implements a UAV radiation monitoring system, which can quickly enter the sky over radioactive contaminated areas for radiation monitoring. The UAV radiation monitoring system mainly includes wide-range G-M counter tube, cerium bromide scintillator detector, data acquisition system and data transmission system. The above devices can be built on the UAV to measure the real-time radiation dose rate and energy spectrum at 0-100 m low altitude.