The convergent boundary between the East Kunlun terrane and the Baryan Hara-Songpan Garze terrane of north Tibet plateau is a large transpressional zone on the south margin of the East Kunlun Mountains. The deformation structures are different between the east segment (A’nyemaqen segment) and west segment (west Datan and east Datan segment). The structures of the A’nyemaqen segment are characterized by superimposed thrust slices with southwest orogenic polarity formed during the stage of Indosinian collision-orogeny and brittle sinistrai strikeslip faults formed during Cenozoic. The west Datan and east Datan segment consists dominantly of an E-W-trending ductile sinistrai strike slip transpression zone companied by a NW-SE trending fold and fault zone on its both sides, which formed 220 Ma ago. The ductile deformation continued till 220 Ma BP and then the deformation was manifested by the reactivation of the brittle sinistral strike-slip deformation structures. Therefore, the large convergence zone on the south margin of the East Kunlun Mountains is a very special tectonic zone which changed gradually from the Constrictive compression in the east segment to the transpression in the west segment. Its formation was related to northeastward oblique subduction of the Baryan Hara-Songpan Garze terrane beneath the East Kulun terrane since Indosinian.