Altun strike-slip fault system strikes northeast-southwest. Within the fault zones, metamorphism, rheology, progressive plastic and brittle deformations are common. Structural forms, including arcuate structures, strike-slip duplex, flow folds, intrastratal folds, S-C fabrics, shear cleavage, quartz c fabrics and en echelon quartz veins, are representative of the products of tectonic movements. Thisfault system experienced two opposite slip senses of faulting recognized by the integration of macro-micro-structures and petrofabric studies. Since its appearance, Altun strike-slip fault experienced initial sinistral, intermediate dextral and final sinistral displacement. The initial sinistral displacement probably took place in Meso- and Neoproterozoic time. Isotopic dating shows that the Altun fault activated at least at the beginning of Neoproterozoic time. The intermediate dextral offset occurred in the Silurian time and probably continued till the end of Devonian time. The dextral structures are offset and superposed by younger sinistral movements as they superposed on the initial sinistral ones. The final sinistral movement took place in late Carboniferous time. The above facts suggest that Altun strike-slip fault system have reversed its shear sense twice since the onset of its faulting. The above-mentioned structures in conjunction with metamor phism and isotopic dating data provide the framework for the development of this fault system. Altun strike-slip fault system strikes northeast-southwest. Within the fault zones, metamorphism, rheology, progressive plastic and brittle deformations are common. Structural forms, including arcuate structures, strike-slip duplex, flow folds, intrastratal folds, SC fabrics, cleavage, quartz c fabrics and en echelon quartz veins, are representative of the products of tectonic movements. Thisfault system experienced two opposite slip senses of faulting recognized by the integration of macro-micro-structures and petrofabric studies. Since its appearance, Altun strike- slip initial experienced initial sinistral, intermediate dextral and final sinistral displacement. The initial sinistral displacement probably took place in Meso- and Neoproterozoic time. Isotopic dating shows that the Altun fault activated at least at the beginning of Neoproterozoic time. The intermediate dextral offset occurred in the Silurian time and probably continued until the end of Devonian time. The dextral str uctures are offset and superposed by younger sinistral movements as they superposed on the initial sinistral ones. The final sinistral movement took place in late Carboniferous time. The above factors suggest that Altun strike-slip fault system have reversed its shear sense twice since the onset of its faulting. The above-mentioned structures in conjunction with metamor phism and isotopic dating data provide the framework for the development of this fault system.