Earthquake focal depth is currently one of the most difficult focal parameters to determine,The focal depth can be accurately determined based on dense near-station observation data,but the focal depth of teleseismic earthquakes cannot be well constrained. The teleseismic reflection phases sP and pP contain effective information for determining the focal depth,and theoretically,the focal depth of teleseismic waves can be effectively constrained. We use domestic seismic stations as well as stations in a certain province as a array,in ordr to improve the signal-to-noise ratio of sP and pP deep seismic phases by processing cross-correlation,seismic phase alignment,and waveform stacking. The IASP91 global model is used to obtain a more accurate focal depth according to the travel time of the seismic phase. In this paper we calculate the focal depths of 64 foreign teleseisms with M≥6 from 2017 to 2020. Compared with authoritative institutions such as GCMT,GFZ,and USGS,the focal depth obtained by this method is relatively reliable. By discussing the effect of rupture duration on pP phase identification,it is concluded that this method has good applicability at different depths when the moment magnitude is between 6～8.5.