During the process of migrating and accumulating toward the Earth's surface, fault- related hydrogen gas is influenced by both tectonic and non- tectonic factors. Based on the spatio—temporal variations of fault hydrogen volume fractions in the Wuhai Basin before and after the Yinchuan Ms 4.2 earthquake on February 20, 2025, and their relationship with regional tectonic features, the authors aim to clarify the significance of the coupling between the geological structures and activities of the Wuhai Basin and the physical/chemical properties of fault hydrogen in earthquake preparation and related fields.Methods:We adopted a research method combining qualitative and quantitative analyses to systematically analyze the annual variation characteristics of fault hydrogen volume fractions in the Wuhai Basin. The Pearson correlation analysis method was used to study the relationship between the changes in fault hydrogen volume fractions at the Molegou trace hydrogen observation point and air temperature as well as air pressure. The interference factors affecting the fault hydrogen volume fractions at the Molegou trace hydrogen observation point were excluded one by one using the elimination method.Results: ① Through the analysis of long- term observation records, data characteristics and abnormal factors from multiple stations, it is confirmed that before the Yinchuan Ms4.2 earthquake, the abnormal hydrogen volume fraction at the Moergou trace hydrogen observation site in the Wuhai Basin is a short- term pre- seismic anomaly. The trend of the abnormal change is that the hydrogen volume fraction value rises rapidly 4 hours before the earthquake the earthquake occurs it turns to decline 1 hour after the earthquake and it recovers to the background value 37 hours after the earthquake. Compared with the existing research cases, the trend of the abnormal change in hydrogen volume fraction is basically the same. The differences lie in the shorter imminent earthquake time and a much larger multiple of the abnormal value compared to the background value. ② Through the relationship between the regional tectonic pattern and short- term anomalies, it is believed that the abnormal increase in hydrogen volume fraction at the Moore Trench trace hydrogen observation point is related to specific tectonic positions. The Moore Trench trace hydrogen observation point is located on the hanging wall steep slope of a normal fault at the mountain—basin transition position in the northern segment of the west margin fault zone of Zhuozi Mountain. In the regional tectonic pattern, the area where the observation point is located has a certain tensile component, which is conducive to the rapid migration of a large amount of hydrogen enriched underground to the surface. ③ Geological structures and their activities (such as stress changes and ruptures), as well as the environment, can affect the migration and diffusion of fault hydrogen. Even within the same fault zone, the changes in fault hydrogen volume fraction will vary due to factors such as the tectonic state, stress changes and groundwater at different locations. Studying the coupling between geological structures and their activities and the physical and chemical properties of fault hydrogen is of great significance in the field of earthquake preparation and other aspects. Conclusions: These understandings provide a basis for the response of the abnormal fault hydrogen volume fraction in the Wuhai Basin to earthquakes and the relationship with tectonics. At the same time, they also have certain guiding significance for the layout of underground fluid observation stations.