The Western Tianshan Mountains are located between the Northern Tianshan Mountains to the south of Kuitun and the Southern Tianshan Mountains to the north of Kuqa. The area is in the junction of the middle section of southeastern margin of the Kazakhstan— Junggar plate and the northwestern margin of the Karakum—Tarim plate in Early Paleozoic, in which the main suture occurred along the Chang'awuzi—Wuwamen ophiolite belt. Based on the geochronological data of each tectonic unit and the study of stratigraphical stystem and ophiolite mélange, writers suggest that the deepseated Huocheng—Haxilegen fault in the south of the Boluokeluo Maintains be the junction of the two Ordovician—Silurian Sarim—Junggar and Wusun—Awulale microplates. The south Tianshan area in the northern margin of the Tarim microplate reflects archipelago nature during Middle Ordovician to Silurian, and the plate motion continued for several billion years. The ocean basin became more narrow in early Late Paleozoic, which last several millions years. The Yilianhabierga area in the north Tianshan Mountains belonged to Early Carboniferous microtrench—arc—basin system. In late Late Paleozoic, the rift was turned into strikeslip fault and pullapart basin system, and the magmatic activities derived from the crust—mantle interaction were extensively and frequent. This period is also the major period of mineralization in the area. In Mesozoic, the area began a geodynamic regime of intracontinental pileup companied by strikeslip fault. In Cenozoic, the whole mountains uplift rapidly due to the collision of Indian plate with Eurasian continent, and formed the current landform with Northern Tianshan, South Tianshan and Ili basin.