A comprehensive statistical analysis was made on the basic features of focal mechanism solutions of 619 ML≥2. 0 quakes from January, 2002 to June 2010 in the Capital Area which was divided into three studying regions in terms of regional tectonic characteristics. The paper conducted a clustering analysis on focal mechanisms of all partitions using the longest distance method of clustering statistical, and studied the characteristics of tectonic stress tensor. The result shows that advantage distribution of P-axis is NNE-NEE and T-axis is NNW-NWW. Most of the hypocentrals are mainly horizontal stress action. Rupture is mainly horizontal strike-slip. The maximum principle compressional stress orientation is NET5° in the west of the Capital Area, NE62° in the middle of the Capital Area, and near EW in the east of the area. The main characteristic of the region tectonic stress field is of horizontal extrusion.[著者文摘]