The Triassic metamorphic rocks south of Kangxiwa fault in Karakorum Mountain area are composed of two sorts of rocks with different remote sensing characteristics. Field work shows that one sort is hypometamorphic rock whose lithologic features, deformation and metamorphic facies are similar to those of Proterozoic Group in Tarim plate, and the other belongs really to Triassic. There exists an unknown deep fault between the two sorts of rocks, which has a distinct linear feature in the remote sensing image. Based on geological analysis, it is considered that this fault is an important geological boundary.