Abstract: Combining the physical and mathematical simulations the strain field and its evolution near locked region are studied. The characteristics of pre-seismic strain fields and displacement fields around the bodies of seismic source with different shapes were discussed, and the strain changes before, just before, during and after earthquakes were also analyzed. Taking notice of the difference around an epicenter from its surrounding permits us preliminarily to explain the strain process of each point relevant to the tectonic conditions, fracturing process and its position in the stress field.