Based on the waveform data and seismic phase reports from the Xinjiang regional digital seismic network, the focal mechanism solution of Aheqi M_S5.2 earthquake and some aftershocks are inverted using the CAP method. Meanwhile, the double-difference localization method is used to relocate the earthquake and its sequence. The results show that the strike, slip and rake are 259°, 44°, and 90° for nodal plane I, and those are 79°, 46°, 90° for nodal plane II, respectively, with a moment magnitude of M_W4.76, and a depth of moment center of 5 km, which suggests that the earthquake is a reverse-type event. The relocation results show that Aheqi M_S5.2 earthquake sequence spreads linearly in the NW direction and is perpendicular to the fault strike, and the depth is concentrated in 3-6 km. Based on this, we comprehensively analyze the historical seismic mechanism solution, geological and tectonic background, and conclude that the Suogedangtawu fault, which is located at the root of Keping thrust tectonic, is the seismogenic structure of this earthquake. This study can provide a certain understanding of the seismic mechanism of strong earthquakes in the contact zone between south Tianshan orogenic belt and Keping thrust tectonic, and provide reference for regional earthquake trend analysis.