In this study, we explore the application of unmanned aerial vehicle (UAV) gamma spectrometry in terrestrial radiometric surveys, with a particular focus on the impact of UAV flight altitudes and rough terrain on measurement. Through field experiments conducted at a rare earth deposit in Sichuan, China, radioactive data were obtained from 509 UAV survey points and 585 ground measurement points. A physical model for measuring ground radioactivity using UAVs is established, and the digital elevation model (DEM) in the survey area is used to correct the height and terrain of radioactivity at the measurement points. By qualitatively and quantitatively analyzing the differences between UAV and ground measurement systems in height and terrain, it concludes that the use of height and terrain correction method can utilize UAV measurement data to indicate ground air absorption dose rates, and the indication of corrected UAV-measured data is enhanced as the correction range expands. The results of this study not only confirm the effectiveness of UAV measurement technology in radiometric surveys, but also provide a new method for radiometric surveys under large-scale and complex terrain conditions, which has significant practical application value in fields such as environmental monitoring, resource exploration, and nuclear security.