The western Tianshan high-pressure low-temperature metamorphic belt in Xinjiang, extending west-east for about 200 km along the Paleozoic suture between the Yili-Central Tianshan and Tarim plates, is mainly composed of garnet, amphibole, omphacite, phengite,paragonite, epidote, chlorite, albite, quartz,sphene, ruble etc. Garnets comprise predominantly almandine componem(Alm45-72)and，next, grossular(GrO9-36)，pyrOpe( Py2-24)and spessartine( Spe0-27).The garnet porphyroblasts contain zoisite, paragonite, albite, sodic amphibole, omphacite and quartz inclusions and are retrograded to chlotites along the margin. Amphibole might be classified imo three types, namely sodic amphibole(glaucophane,ferro-glaucophane, crossite, riebeckite, magnesio-riebeckite)，sodic-calc maphibole(barroisite and win- chite) and talc amphibole(actinolite).The sodic amphiboles assume coarse-,medium-,fine-grained and fibrous assemblages, with the majority being fine-grained(0.1-0.5 mm)in size. A few sodic amphiboles are slightly retrograded to chlorites or actinolites.The jadeite content of omphacites in eclogues is between 39.38% and 54.14% averagly 45.48%.The cation number of Si of phengites changs from 3.31 to 3.57，averaging 3.41.The ration number of Na of paragonites changes from 0. 64 to 0. 90, 0. 85 on the average. The conditions of peak eclogue facies metamorphism are estimated to be 520士80℃and 1 .2-1 .4 GPa. The metamorphic mineral assemblages reveal that the high P/T belt has underdone a metamorphic evolution process from lawsonite-blueschist facies through eclogite facies and epidote-blueschist facies to greenschist facies.