According to the measurement of the China Earthquake Networks Center, at 17:00:08 on June 1, 2022, Beijing time, a M_S6.1 earthquake occurred in Lushan County, Sichuan Province. Three minutes later, another M_S4.5 aftershock (the largest aftershock of this earthquake sequence) occurred. From the epicenter announced by the China Earthquake Networks Center, the epicenter of M_S6.1 mainshock is very close to that of the 2013 Lushan M_S7.0 earthquake (about 10 km), and the seismogenic fault of the former event is still controversial nowadays. The focal mechanisms of the 2022 mainshock and its largest aftershock may shed more light on this problem. In this paper, firstly based on the waveform data recorded by the broadband seismic stations deployed by the Sichuan Seismic Network, we use ISOLA software for waveform fitting to obtain the double couple focal mechanism of two earthquakes. The result of 2022 mainshock as follows: 222°/43°/104° (nodal plane Ⅰ: strike/dip/slip) and 23°/48°/76° (nodal plane Ⅱ), centroid depth 16 km, and moment magnitude M_W5.9. The result of aftershock is shown as 237°/36°/109° (nodal plane Ⅰ), 34°/56°/76° (nodal plane Ⅱ), centroid depth 17 km, and moment magnitude M_W5.0. These two earthquakes are mainly trust type. Secondly, based on the continuous waveforms recorded by the seismic stations within 150 km epicentral distance during 2022-06-01 to 2022-06-10, we use LOC-FLOW software to identify and relocate the aftershocks. A total of 838 aftershocks are obtained, most of which are distributed in the northwest of the mainshock in the horizontal map. In the depth profile, on one hand most aftershocks are distributed along the up-dip direction of the mainshock, on the other hand it indicates that the fault plane southeastward inclines. Theoretically, the recorded waveform can be calculated by the convolution of source time function, propagation path effect and instrument response function. Assuming two events closely nearby each other are recorded in the same seismic station, the difference between two waveforms approximately reflects the difference of earthquake rupture process due to the same instrument response and similar propagation path effect. In this paper, the mainshock waveforms of two Lushan events recorded by 31 azimuthal stations are compared and analyzed, and it turns out two waveforms at each station show good consistence in the period range 10~20 s, indicating the rupture process for these two events may have similarities to some extent. The study area locates in the southern Longmenshan fault belt, the surface is mainly dominated by the faults with NE-SW strike and NW dip. However, according to the focal mechanisms and aftershock analysis in this study, we speculate that the 2022 Lushan earthquake should occur on a blind thrust fault inclining to SE. It is consistent with the NW-SE tectonic stress field in this area that has long been subjected to lateral extrusion on the Tibetan Plateau.