Abstract:The middle section of Qilian Mountains is considered to be a key area where strong earthquakes might occur in recent years, but the earthquake situation in the study area is still unclear. Therefore, it is of great practical significance to study the anomaly characteristics of geoelectric observation data recorded by Shandan station in Zhangye City, Gansu Province. On September 16, 2019, an MS5.0 earthquake occurred in Ganzhou District, Zhangye City, Gansu Province. Before the earthquake, there were obvious short-impending anomalies in the observation data of Shandan earth resistivity and geoelectric field, with an epicenter distance of 63 km. In this paper, the anomalies were analyzed and summarized, and they were considered to be reliable earthquake precursor anomalies after excluding the surrounding observation environment, observation system, natural environment, magnetic storm, and other factors. The abnormal forms of earth resistivity and geoelectric field observation data in different channels were also discussed. It is found that the earthquake occurred when the above-mentioned observation data had a turning change or the rising (falling) rate changed during the anomaly duration