Abstract: Based on the waveform data from seismic stations near the epicenter, we use the CAP method to obtain the focal mechanism solution and centroid depth of the Pingshan M4.3 earthquake. In order to get a more accurate result, we use the sPL phase to measure the focal depth. The results show the parameters of the focal mechanism solution of the Pingshan M4.3 earthquake are as follows: the nodal plane Ⅰ has a strike of 310°, a dip of 45°, a rake of 35°; the nodal plane II has a strike of 194°, a dip of 66°, a rake of 129°. The P-axis has an azimuth of 256° and an inclination angle of 12°. The focal mechanism solution exhibits a compressive stress state in the NEE-SWW direction, which is basically the same as the direction of the tectonic stress field in North China. We conclude that the seismogenic fault is a reverse hidden fault with a slight strike slip component.