| China is a region with the strongest earthquakes in the global continent, and a country with many and strong earthquakes. The Qinghai-Tibetan Plateau, lies in the Southwest region of China, with the highest and strongest seismicity. It is a product of the ongoing collision be-tween Indian and Eurasian plates, with complex geological structures,active faults and strong curst motion. It becomes an ideal region for studying on the intra-plate crustal deformation and seismic mechanism.With the rapid development and widespread use of space geodesy techniques, repre-sented by Global Positioning System, it provides many data with large scale, high accuracy and quasi-realtime for the development and application the geodetic inversion. The space scale of GPS data vary from region to the global, and its time scale vary from seconds to years. Its precision of relative positioning for long baseline can reach the magnitude of 10-9. The quantitative image of crust motion with high precision and space-time resolution by GPS, is the important basic data for research on continental dynamics. Therefore, GPS data is used for research on crustal movement and deformation in central and east Qinghai-Tibet Plateau in this thesis.With high precision data process of six repeated GPS observation data, which were col-lected in 1993,1995,1997,2000,2002, and 2007 separately, the present-day 3D crustal move-ment in the Qinghai-Tibetan Plateau is obtained. According to the location of the monitoring sites, the crust motion and strain parameters of the Himalayan sub-block and the Tibetan sub-block are obtained. It shows that the rates of crust motion in the Himalayan sub-block are (19.0±0.5)mm/a, (10.8±0.3)mm/a and (3.6±0.4)mm/a in SN, EW and vertical direction, sep-arately. The Himalayan sub-block is mainly under compressing strain, and the maximum compressing rate is (-26.6±3.8)×10-9/a and with the extension rate of (9.4±0.9)×10-9/a in the direction of N(33.8±3.3)0E. The rates of crust motion in the Tibetan sub-block are (9.1±0.6)mm/a, (8.5±0.7)mm/a and (3.3±0.3)mm/a in SN, EW and vertical direction, sepa-rately. The Tibetan sub-block is mainly under compressing strain, and the maximum com-pressing rate is (-11.4±2.9)×10-9/a and with the extension rate of (6.2±1.0)x10-9/αin the direction of N(55.8±4.3)0E. It also shows that present 3D crustal movement in the Qinghai-Tibetan Plateau is characterized by compression in NS direction, extension in EW direction, and vertical uplift.On the basis of plotting sub-blocks in Sichuan-Yunnan area, by using GPS velocity ob- servations, collected from the Crustal Motion Observation Network of China between 1998 and 2004, and seismic moment tensors, collected from the Harvard centroid moment tensor between 1903 and 2003, the parameters of crust motion in these sub-blocks are inverted. It shows that the predominant direction of crust motion in East-Zang sub-block is N97.10E at the rate of 22.3mm/a, and N127.90E,17.9mm/a in West-Chuan sub-block, N146.70E,15.8mm/a in Mid-Dian sub-block, N167.00E,9.7mm/a in Yinzhi sub-block, separately. Slip rates of some active faults are calculated by velocity profiles. It shows that the slip rate and shortening rate of Xianshuihe fault are (10.0±1.0)mm/a, (2.2±1.0)mm/a separately. And the right slip rates of Jinshajiang fault and Red river fault are (3.7±1.2)mm/a, (7.3±0.9)mm/a separately. Furthermore, the mode of curst deformation in Sichuan-Yunnan area is discussed. The extru-sion velocity of the Qinghai-Tibetan Plateau in EW direction is far slower than the velocity predicted by the continental extrusion model, but adopted by clockwise rotation and inner deformation of the crust in Sichuan-Yunnan area.Using the method of time series analysis, the data of GPS continual observation sites in the zone of Wenchuan Earthquake is processed, and the postseismic displacement of these sites is obtained. The result shows that the relax time of postseismic deformation is about 38 days, and the hanging wall is with the vertical uplift and horizontal movement in south-east direction. Furthermore, adopting the coseismic dislocation model by others'study, using PSGRN/PSCMP procedure, the postseismic deformation caused by the viscoelastic relaxation is simulated. The result shows that the best thickness of the elastic layer is about 45 km, and the best coefficient of viscosity is about 1.8×1019 Pa·s in the zone of Wenchuan Earthquake.
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