Abstract: Based on the three-component waveform data of regional broadband stations of Heilongjiang, Jilin and Inner Mongolia digital seismic networks, the full waveform moment tensor inversion for the M_S5.7 earthquake occurred in Ningjiang district of Songyuan, Jilin Province, on May 28, 2018 is carried out, and the focal mechanism solution and centroid position of the earthquake are obtained. And then the hypocenter-centroid method is used to determine the actual seismogenic fault. The results show that the moment magnitude is M_W5.2, centroid position is （45.225°N, 124.685°E）, and centroid depth is 7 km. The mechanism parameters of the earthquake are: strike 217°, dip 82°, rake 164° for the nodal planeⅠ , strike 309°, dip 74°, rake 8° for the nodal planeⅡ , and the event is of strike-slip type. Moreover, double-couple component is 96.4%, and variance reduction is 93%. The hypocenter-centroid plot indicates that the hypocenter is close to nodal plane Ⅰ , which is consistent with the strike and dip angle of the Fuyu-Zhaodong fault. Therefore, it is indicated that the Fuyu-Zhaodong fault is the real fault plane.