Abstract:The Yangjiang earthquake sequences from January, 2004 to May,2007 were relocated with the double-difference location algorithm. The results show that two ML≥2.0 seismicity belts distributed in Yangjiang area before Yangjiang M4.9 earthquake occurred on 17th September, 2004, the direction of one belt was NNW and the other was NW. The direction of NNW ML≥2.0 seismicity belt was consistent with the direction of nodal plane Ⅱ of focal mechanism and the focal rupture azimuth. The focal depth of NNW seismicity belt deepened gradually in one month before the 4.9 earthquake and it occurred at the southeast edge of NNW seismicity belt.