A series of large- scale NW- trending sinistral strikeslip faults has developed in the northern Qinghai- Tibet Plateau. It is generally believed that these sinistral strike- slip faults are still active at present and the eastern Tibet Plateau is extruded eastward accompanied by strong block rotation under the effect of the sinistral strike- slip. This study took the central fault of Bayan Har Mountain between East Kunlun sinistral strike- slip and Yushu sinistral strike- slip fault zone (and its surrounding structural traces) as the research objective. Based on the direct sign of faulting structure (distinct linear tracers) and structural geomorphic signs (water system displacement caused by fault scarp and valley, compressive ridge, rifting and strike- slip) and lateral overlapping of various diluvial fans, the spatial distribution, scale, activity nature, relative activity time and activity amplitude of NW- trending active faults and NE- trending active faults were analyzed by high resolution SPOT5 and medium resolution ETM remote sensing images in the research area. Combined with remote sensing analysis, field verification and statistical analysis on the scale and the extension direction of water system distribution and ground fissure along conjugate separation fracture around the faults, the late Quaternary stress field was restored. The study shows that the NW active faults are characterized by dextral strike- slip and thrust movement and the NE trending active faults are characterized by sinistral strike- slip and normal slide faulting movement. Both of them were the products of NW and NE strike- slip under the late Quaternary NNE direction (2°) compression stress. The discovery of the NW- trending dextral strike slip indicates that the northwestward sinistral strike slip movement which had been widespread since Quaternary in the northern Tibetan plateau may have been terminated in the Middle Pleistocene. On the basis of the analysis above, evolution trend of lake basins under the same stress condition which have different extension directions was discussed in the study, i. e., under the effect of the NNE compressive stress, the NE- extensional Cuokanbaangridong lake is in a state of near EW extension, while changes of the NW- extensional Kabaniuerduo lake is not significant.