The transpressional shear zone, commonly recognized in the convergence plate margins and collision orogens, has played a significant role for accommodating accretion, collision lateral extrusion parallel to orogens. The North Qaidam tectonic belt, which is located in northern Tibet, was regarded as resulting from closure of Proto- Tethys, continental deep subduction and post- orogenic extension collapse during early Paleozoic era. Recently, an NWW—SEE trending dextral transpression ductile shear zone was newly recognized in the Chahanhe area, eastern North Qaidam Mountains. In this contribution, we present macro- microstructural observations, quartz C- axis fabric analyses, quantitative structural data (including kinematic vorticity, paleo- stress and strain rate), and combine with zircon U- Pb dating data, to investigate the type of the transpression of the ductile shear zone and discuss its tectonic evolution. The macro- to micro- structural feature and quartz C- axis fabric in XZ planes show that the Chahanhe ductile shear zone is characterized by dextral strike- slip shear sense. Finite strain and kinematic vorticity in deformed rocks indicate a slightly prolate ellipsoid near plane strain, suggesting a transpressional style. Mineral recrystallization mechanism, quartz c- axis fabrics slip system and opening- angle thermometer reveal that the Chahanhe ductile shear zone developed under 500 to 553 ℃, corresponding to a mid- crust level (16～18 km). Combining with dynamic recrystallization particle size of quartz, the differential stress and strain rate were estimated to be 29～30 MPa and 10-12/s, respectively. Zircon U- Pb dating of diorite involved in ductile shearing gave an age of 432±3 Ma. Combining with previously geological data suggests the timing of the ductile shearing deformation between middle Silurian and early Devonian (432～396 Ma). The integrated data indicate that the Chahanhe ductile shear zone is characterized by combination of horizontal contraction perpendicular to the orogenic belt and lateral extrusion parallel to the orogenic belt, accompanied by a part of top- to- the south thrust component, resulted from oblique convergence and collision during late early Paleozoic orogeny.