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Based on the lateral segmentation and vertical stratification characteristics of the crustal medium in Sichuan-Yunnan region, and the asymmetry of the static dislocations on the coseismic fault plane of the Wenchuan MS8. 0 earthquake, we built a three-dimensional viscoelastic finite element model of the crust in the Sichuan-Yunnan region. The postseismic impact of the Wenchuan MS8. 0 earthquake on the Sichuan-Yunnan region was studied. The results show that: ① The far-field horizontal deformation caused by the viscoelastic relaxation of the medium in the 10 years after the earthquake is about 0-20mm within the Sichuan-Yunnan diamond-shaped block, which has a greater influence on north side and smaller on south side. ② In the 10 years after the earthquake, the far-field vertical deformation caused by the viscoelastic relaxation effect of the medium is small, and it shows an increase of about 0-4mm in most areas of the Sichuan-Yunnan diamond-shaped block. ③ The Xianshuihe fault and the east segment of the East Kunlun fault, which are close to the seismogenic fault, show a high gradient on deformation fields after the earthquake. ④ In order to compare with the strong earthquake activity in the Sichuan-Yunnan region after the Wenchuan earthquake, the horizontal stress state and the Coulomb failure stress change of the active block boundary are also calculated. From the spatial distribution of the coseismic and postseismic displacement field, the fault activity characteristics reflected by the stress state and the stress loading of the fault layer reflected by the Coulomb failure stress change, there is a certain correlation with the spatial distribution of strong earthquake activity in this region.