Abstract: In this paper,using the integral expression of additional gravity field due to displacement of point mass within the deformed medium,the relation between the Bouguer anomaly on the ground and permanent deformation caused by fault movement for a long time in Maxwell half-space is quantitatively studied. A general method for inversely estimating the fault slip trend in geological time by the Bouguer anomaly distribution nearby the fault is obtained,which is principally valid in identifying the fault movement,especially for strike-slip mode in a plain region.By means of a numerical integration,the authors have calculated gravity anomalies on the ground associated with the fault motions in Luannan region. By comparing the theoretical results with the practical gravity measurements,the authors come to a conclusion that the right-lateral strike-slip and dip-slip of a fault may occur in the geological time.