Based on the observation of local GNSS velocity fields in China from 2017 to 2020,and the time series data from CMONOC,the tectonic deformation and evolution characteristics before the 2022 Luding M_S6.8 earthquake were analyzed in details,from the perspectives of baseline change characteristics and multi-scale crustal strain parameters. The following understandings were obtained:① The accelerated compression of baselines of Ganzi-Xiaojin,and Luhuo-Xiaojin in the Bayan Har block before the 2021 Maduo M_S7.4 earthquake,show that the boundary faults are decoupled and accelerated to the south and east after the co-seismic rupture,which leads to the acceleration of the strain energy accumulation rate and the increase of the seismic risk in the Sanchakou area bounded by the south section of Xianshuihe Fault and the southwest section of Longmenshan Fault. ② The 2022 Luding M_S6.8 earthquake is located in the weakening zone of the high shear strain edge of the large strike-slip fault zone,and the tensile zone of the strain is perpendicular to the fault direction,which indicates that the decrease of the normal strain in the locked background is closely related to fault rupture and earthquake nucleation.