Abstract: In response to the need for large-scale exploration of radioactive minerals in high-relief areas, this study developed an airborne gamma-ray spectrometer based on small-sized NaI (Tl) crystals, which was integrated with the F-120 unmanned aerial vehicle (UAV) to form an airborne gamma-ray spectrometry (AGRS) system. The UAV-AGRS system was applied to the follow-up geochemical survey of uranium deposits in a certain area of South China. The survey results show roughly consistent locations and morphologies for high-anomaly zones with the ground gamma-ray spectrometry results. Moreover, the results of this study exhibit more detailed anomaly morphologies, and more significant responses of uranium content-related uranium channel data to known uranium occurrences in the study area, suggesting superior data. Therefore, the UAV-AGRS system shows promising potential as an effective alternative to ground gamma-ray spectrometry for the follow-up geochemical survey of uranium deposits in high-relief areas.