The Maduo MW 7.3 earthquake occurred at 2:04 local standard time on May 22, 2021, in Maduo County, Golog Tibetan Autonomous Prefecture, Qinghai Province, China. In this chapter, the regional seismogenic environment, co-seismic displacements, and evolution of early post-seismic deformation are studied by using the long-term accumulated GNSS observations of the epicenter and its surrounding areas. Firstly, we obtained the horizontal GNSS velocity field, which indicated the seismogenic environment of the epicenter and its surrounding areas is mainly sinistral shear. The relative crustal deformation of the main boundary fault accounts for 60% of the relative movement of the whole Bayan Har block, while the internal one accounts for 40%. Secondly, we calculated the GNSS strain rate field by using a multi-scale spherical wavelet method considering robustness. The result shows that the significant strain accumulation areas are distributed along the main boundary fault of the block, and the epicenter is located in the transition zone from the great strain rate values to the low one. Finally, the co-seismic and early post-seismic deformation were calculated by continuous GNSS observations. Two strategies were adopted to calculate the co-seismic displacements, the difference between them indicated the co-seismic displacements can be obtained more accurately by using the strategy of 4 h observations after the mainshock, and the results of a single day strategy have included the early post-seismic deformation. The significant post-seismic deformation was obtained at station QHMD, and its direction is consistent with the co-seismic one. The logarithmic attenuation model which characterizes mainly after-slip deformation can accurately model the observed values. The post-seismic deformation in the first 5 days accounts for 72% of the first 20 days.