Abstract:According to the sP and pP characteristics of the seismic wave Sp phase and the teleseismic depth of the basement interface of the near-seismic sedimentary layer, we analyze the focal depth of the February 12, 2018 Yongqing M4.3 earthquake. F-K wave number and frequency method are used to fit. The near-seismic theoretical waveform and Teleseis method fits the far-seismic theoretical waveform and we compare it with the actual waveform to test the focal depth. The results show that the focal depth of the Yongqing earthquake is in the range of 16 km to 17 km. From the analysis of the location of the earthquake and the depth of the source, the earthquake occurred in the upper middle crust, similar to other seismic events in the area.