Abstract:With the point source dislocation model in layered medium and using the records of mobile seismic network,we calculated the focal mechanism solutions of 112 ML≥1.5 aftershocks of the JiujiangRuichang earthquake. By analyzing the results,the conclusions are obtained:1) The predominant rupture strikes of the JiujiangRuichang earthquake aftershocks are NNW and NEE, its predominant dip angle is between 50 and 60°,and its predominant slip angle is between -60 and -100°;2)The pressure axis of epicentre stress field is distributed in the near diretion of EW,and its tensile axis is distributed in the near diretion of NS. The predominant orientation of these solutions is close to the character of tectonic stress field in north Jiangxi.