Based on the broadband waveforms recorded by Yunnan and Tengchong Volcanic Digital Seismic Networks, the authors inversed the focal mechanism solutions of the main shock of Yingjiang M_S 5.8 earthquake sequences and M_S≥4.0 foreshocks and aftershocks in 2011 by using CAP method. Combined with stress field and tectonic settings comprehensively, the seismogenic dynamic background of Yingjiang M_S 5.8 earthquake was under the double effects which were northeastward compression of India Plate to Eurasia Plate and northeastward subduction of Burma arc to Baoshan-Tengchong block. The Baoshan-Tengchong block moved horizontally along NE direction, which leaded to the left-lateral strike-slip motion of Dayingjiang Fault.oft-com:office:office" />