The complex geological structure and highly active surface and tectonic processes of the eastern Himalayan syntaxis (EHS) resulted in many large earthquakes, making it an important region for studying the dynamics of continental collision. To monitor seismic activity in this region, we deployed a six‐station temporary real‐time telemetered broadband seismic network, the Namche Barwa temporary seismic network (NBTSN), since December 2016. This network enabled us to obtain more accurate results on the crustal and mantle structures of the Namche Barwa region and to investigate the mechanism of the formation of the EHS. We combined data from these temporary stations and other permanent stations to produce detailed models of seismic activity in this area. On 18 November 2017, a shallow M 6.9 earthquake occurred in Mainling Prefecture, Nyingchi City, Tibet, just within the monitored area. This provided a unique opportunity to test the performance of the NBTSN during a major earthquake. In this study, we reported the key features of the NBTSN, including details of the seismic network deployment, station noise levels, and overall earthquake‐monitoring capacity. The presence of the temporary stations resulted in an improvement in the minimum detectable magnitude from an original level between 2.3–2.8 and 1.5–2.2. We obtained preliminary results using seismic data acquired during the 2017 Mainling earthquake, including detailed relocations of the mainshock and aftershocks. We also analyzed the frequency–magnitude distribution of the relocated aftershock sequence, and observed a low ‐value of 0.86, indicating that seismic hazard in this region remains high. Overall, these results reveal the potential application of this network to explore the physical mechanism of large block boundary earthquakes and resultant geological disasters.