Kuluketage area is located in the northeastern margin of the Tarim basin. There are a lot of plagioclase amphibolites in the form of lens in the TTG series, with their long_axis consistent with the strike of gneissic schistosity. On the basis of detailed researches on petrology, geochemistry of REE and trace elements and Sm, Nd isotopic compositions, two types of plagioclase amphibolites have been recognized in Kuluketage area. The protolith of the plagioclase amphibolites in Tuogelakebulake area in the northern part of Kuluketage region was basalt which might have been formed in the mid-ocean ridges. The amphibolites have the flat REE pattern similar to that of MORB with (La/Yb)Nbeing 0.66—4.23 andδEu 0.82—1.15. The samples in Kuokesu area located in the southern part of Kuluketage region are characterized by the light REE-enriched pattern with (La/Yb)Nbeing 2.71—10.84 andδEu 0.81—1.07. This may indicate that plagioclase amphibolites are similar to island arc basalt. The magma of all the plagioclase amphibolites was derived from the mantle, with no crustal contamination in the process of uplifting.