Abstract: Baiyin region ,located in the eastern sector of Northern Wilian orogenic belt, can be divided into four tectonic units (B1, B2, B3,B4). B1 is a part of central Qilian metamorphic block. B2 occurred as an accretionary complex produced during subduction of ancient Qilian plate. B3 and B4 respectively belong to Caledonian volcanic arc and remnant back-arc basin. Two phases of ductile deformation are recognized. The first phase of ductile deformation is characterized by NE-SW stretching lineation nearly perpendicular to the orogenic belt. The shearing displays a series of N to S thrust-imbricate structures related to northward subduction of ancient Qilian ocean plate. The second ductile deformation formed for ductile strike-slip shear zones with subhorizontal NWW-SEE stretching lineations and sub-vertical foliations. Shearing observed in shear zones indicates dextral strike slip. Microstructure, quartz c-axis fabric and syntectonic metamorphism show that deformation condition ranges from 500℃ to 350℃ (from SZ1-SZ4). These ductile shear zones are interpreted as intracontinental extrusion postdating the Caledonian subduction and collision.