Three Envisat images from ESA were used to derive the pre-and co-seismic deformation interfereo-grams caused by the Damxung Ms6. 6 earthquake of Oct. 6,2008 ,by using InSAR. The result shows no signifi-cant crustal motion more than 4 months before the earthquake, but a maximum co-seismic displacement of a-bout 0.3 m in an epicentral area of 20 km×20 km. The deformation field was symmetrically distributed about a NS axis, where the west side subsided and the east side uplifted. We used a linear elastic dislocation model in half space and a nonlinear constraint optimized algorithm to estimate the slip distribution along the fault. The results indicates that the epicenter is located at 90.374°E,29.745°N with a moment magnitude of Mw6. 35.The earthquake is dominated by normal faulting with a maximum slip of 3 m on a 12 km×11 km fault plane striking S189°W,dipping 60° to NW at a depth of 9.5 km,and is located at a sub-fault of the southeastern Piedmont of the Nyainqentanglha mountains. The relatively shallow depth of earthquake is related to relatively high heat flow in the area.