The Jiashi M_S5.5 earthquake occurred on September 4,2018 in Xinjiang Uygur Autonomous Region,the epicenter is located in the northwestern margin of the Tarim block,in the seismic area of 1997-1998 Jiashi strong earthquake swarm. The Jiashi earthquake has M_S4.7 foreshock,the largest aftershock magnitude M4.6,preliminarily determined as a pre-main-aftershock sequence. The precise positioning results show that the aftershocks are distributed along the NE direction,and the depth of the main shock is basically the same as that of the 1997-1998 Jiashi strong earthquakes. The seismogenic fault rises steeply. In this paper,the seismogenic process of this earthquake is analyzed from the aspects of regional tectonic environment,focal mechanism solution and aftershock distribution. It is considered that the earthquake occurred on the southeastern margin of Jiashi concealed fault,which is a new tectonic activity in the Jiashi strong earthquake swarm area from 1997 to 1998. The calculation results of sequence parameters and apparent stress show that strong earthquakes in the Jiashi earthquake area are unlikely to occur in the near future.