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The Chinese Altai in the Central Asian Orogenic Belt developed as a subduction-related orogen in the Neoproterozoic to Paleozoic.It was modified in the Permian by deformation,magmatism and metamorphism,which were supposed to be associated with the collision between the Chinese Altai and the East Junggar.However,the exact collisional process and associated structural expression are still unclear.Here we conducted structural observations on the major shear zones,dome and basin structures and zonal metamorphic sequences in the southern Chinese Altai,which combines with new chronological data in an attempt to constrain the geodynamic processes for the convergence of the Chinese Altai with the East Junggar.Our results show that the convergence between the Chinese Altai and the East Junggar is characterized by a cycle of crustal contraction,extension and transpressional contraction.The transpressional deformation is responsible for the origin of the dome and basin structures and zonal metamorphic sequences in the southern Chinese Altai.