Abstract: Grounding systems are the core infrastructure to ensure the reliable operation of field geophysical survey equipment and industrial electrical systems, as well as to prevent the risk of electric shock to personnel. In response to common issues during on-site grounding resistance testing, such as abnormal data fluctuations, excessive resistance values, and measurement distortions, this paper first explains the composition and testing principles of grounding resistance. It then systematically analyzes various factors leading to increased measurement errors and actual resistance exceeding standards from five aspects: testing operations, soil characteristics, environmental interference, lead connections, and construction quality. Based on this analysis, optimization measures are proposed from the perspectives of testing accuracy control and engineering resistance reduction renovations, and an application verification is conducted using a grounding rectification case for a geophysical instrument room in the Gobi region of Xinjiang. Results indicate that the combination of deep well grounding and resistivity-lowering agents can effectively reduce grounding resistance in areas with high soil resistivity and demonstrates excellent seasonal stability. The research findings can provide engineering references for the testing, operation, maintenance, and rectification of grounding systems under similar field conditions。