Abstract:Based on the observation data of flowing gravity in the capital area from 2017 to 2019, we analyze the gravity changes at different time scales before the M4.5 earthquake in Tangshan, Hebei province, on December 5, 2019. The results show:1) The image of the variation of the 0.5 a scale gravity field well reflects the evolution process of the earthquake: “in 1 a before the earthquake, the gravity field continued to rise(positive) change-the local reverse(negative) change before the earthquake-the earthquake occurred near the zero contour line of the gravity gradient zone”; 2) The 0.5 a, 1 a and 2 a scale gravity fields before the earthquake, show that the earthquake occurred near the zero contour line of gravity change; 3) The change of gravity observed before the earthquake may be caused by the upwelling process of deep thermal materials.