Abstract: Several ophiolitic melange belts are exposed in West Kunlun, Xinjiang,in which the Subashi ophiolitic melange belt is occurred in Yurungkash-Aksu area in Yutian County. 2 gabbro samples from the southern part of Subashi ophiolite have been dated by LA-ICP-MS zircon U-Pb dating and obtain the age data of (352.7+3)Ma and (261.9+2.2)Ma. It is determined that this ophiolite was formed in early Carboniferous to Middle Permian. After comprehensively analyzing the sedimentary rocks and related marginal geological bodies associated with the mélange belt, it is basically determined that the Subashi ophiolite belt should be a remnant of the valerian oceanic crust, which is consistent with the formation age of the ophiolite in Muztagh and Anemaqen. The ophiolite belts mentioned above constitute the Mazha-Kangxiwar-Muztagh tectonic belt, which is equivalent to the fourth suture zone of the Qingha-Tibetan Plateau.