There was a ML4． 0 earthquake swarm since February 2，2012 in the Gaizhou area． The Gaizhou ML4． 0 earthquake swarm was located on the northern Jinzhou fault and the southern part of Haicheng-Yingkou fault． The overall earthquake distribution was in the northwest direction． We used the earthquake observation reports recorded by the Liaoning seismic stations during the period February 2012 ～ September 2013，and with the double difference location method，obtained the earthquake location of Gaizhou earthquake swarm． The result of earthquake location showed the earthquake swarm distributed along the NW-trending，indeed． As the earthquake swarm developed，the depth of earthquakes became shallower． Analysis showed the Gaizhou earthquake swarm occurred in a new NW-trending faults between on the Jinzhou fault and Haicheng-Yingkou fault．