Abstract:Using mobile gravity observation data in Jiangsu from 2019 to 2021, we analyze the variation characteristics of the gravity field at different time scales before the Changzhou M4.2 earthquake in Jiangsu. The results show that: 1) The 0.5 a scale gravity field change image better reflects the change process of this earthquake’s decline-turn up-continuous rise-reverse change, and the evolution of seismogenesis near the zero contour; 2) The 0.5 a and 1 a scale gravity fields before the Changzhou M4.2 earthquake both show that the earthquake occurred near the zero-contour line of gravity change.