Abstract: On November 14th 2001 an earthquake with magnitude of M S 8.1 occurred at the northern Qinghai-Xizang Plateau in China. 58 old GPS stations at the surface rupture and the surrounding areas were re-set up after the earthquake and new GPS measurements were carried out to compare with old GPS measurements took several years before the earthquake. 16 new stations were also established immediately after the earthquake across the surface rupture, among them 4 has been continuously observed and the rest have been measured six times since December 2nd 2001. The co-seismic displacements calculated by GPS measurements show that while the deformation caused by the earthquake is in an area within 88°～97°E and 32°～38°N, much of the deformation was restricted along the surface ruptures. The fault movement was left-lateral strike-slip with compressional components. Near the Kunlun Pass the GPS measured displacement is about 2.6m which is close to the displacement investigated on site. The co-seismic displacement south to the surface rupture is decreasing gradually and the direction of the displacement is relatively consistent, while the displacement north to the surface rupture is concentrated along the southern edge of the Qaidam Basin and the displacement decreased rapidly within the basin, showing crust property difference between the Qaidam Basin and the interior of the Qinghai-Xizang Plateau. The preliminary result from the GPS measurements has shown that the creeping displacement across the rupture is more than 47% of the total for the first two weeks, and the creeping rate decreases rapidly afterwards, showing the rheological property of the deformed crust in that area of the Plateau. There is no obvious relative movement along the faults east to the surface rupture which shows that faults in this area may still be locked.