Abstract: Eclogite from Xitieshan area occurs as lenses within granitic gneiss and pelitic gneiss. According to the characteristic minerals, these eclogites can be divided into two types, i.e., phengite eclogite and hornblend eclogtie. Coesite pseudomorph inclusion in omphacite is found in the phengite eclogite. Using garnet-omphacite-phengite geothermobarometer, the peak P-T conditions of Xitieshan eclogites are P=2.71~3.17GPa and T=751~791℃ which is consistent with the presence of coesite pseudomorph inclusion in omphacite. Therefore, we infer that some of eclogites in Xitieshan have undergone UHP metamorphism as the other blocks such as Dulan eclogites in North Qadam. Based on the PT pseudosections calculation by the Thriak/Domino programme, two stages of retrograde metamorphic evolution have been simulated, i.e., the early isothermal decompression process followed by a late process of decreasing temperature and pressure. The mineral compositions and texture changed a lot during retrograde metamorphic evolution. The composition of garnet made little changes during the ITD (Isothermal Decompression) process, however, pyrope contents decreased obviously in the rim of the garnet when amphibole appeared, and then formed the pargasite+plagioclace coronas around garnet. Jadeide contents of omphacite decreased in the presents of active fluid during retrograde metamorphism. The appearance of Di+Ab+Amp symplectites around omphacite indicated a fluid absent condition. Phengite decomposed into the assemblage of muscovites+biotites and a little K-feldspar+quartz. Amphibole changed from magnesiokatophorite to pargasite, which indicated a transform from calcic-sodic to calcic amphibole.