Abstract: Based on the historical data of the 1679 Sanhe-Pinggu M8.0 earthquake and paleo-earthquake data revealed by trenching on the Xinxiadian fault, together with the principle for earthquake recurrence in-situ on a fault or a segment, the maximum potential magnitude in the future on some segments of Xinxiadian fault is evaluated by taking consideration of the concept that strain energy accumulates on both sides of a fault. This illustrates that due to difficulty in determining the strain and stress in deep crustal rocks, the accumulated strain energy cannot be determined accurately. On the other hand, when the strain （deformation） localization is combined with the local instability critical conditions of the rock-fault system, the decreasing rate of deformation belt could be used for prediction of earthquake occurrence.