A set of meta-argillaceous rocks mainly composed of biotite plagioclase gneiss have been newly discovered in Caojian, Yunlong County, western Yunnan Province, which are existent in the form of structural lenses, with small outcrops and well-developed medium-high metamorphic minerals, which is obviously different from the feature of surrounding rocks. Petrographic study shows that gneiss has obvious mineralogical records of subduction-exhumation, and there is also a paragenetic mineral assemblage of kyanite+aluminum amphibole, and the corresponding metamorphic pressure should have reached 1.0 GPa or higher. The metamorphic temperature and pressure of rocks calculated by GBP average temperature and pressure meter method are 566~623℃ and 0.36~0.53 GPa respectively. In addition, there is a small amount of siliceous muscovite minerals in gneiss. According to the p-T visual profile of phase equilibrium simulation and the characteristics of its maximum silicon atomic weight of 3.23, it is inferred that the rock belongs to blueschist. According to the comprehensive study, the biotite plagioclase gneiss belongs to high-pressure metamorphic rocks (the minimum metamorphic pressure in peak period is about 1.60 GPa), and these data provide new information in search for high-pressure metamorphic rocks in the northern part of Changning-Menglian junction zone, and also show that Changning-Menglian junction zone is a continuous high-pressure and ultrahigh-pressure metamorphic zone.