Blueschist sporadically occurs as lenses within Lancangjiang metamorphic complex. The combined studies of petrography, geochemistry, genetic mineralogy and phase equilibrium modeling for blueschists within Xiaoheijiang-Shangyun area provide a significant insight into protoliths and metamorphic evolution. Geochemical features show that they have similar rare-earth elements(REE) patterns, with slight Eu anomalies. REE and trace elements compositions have an affinity to those of oceanic island basalts(OIB),suggesting that their protoliths were OIB-type basalts. Petrological studies show that blueschists contain two distinct mineral assemblages characterized by glaucophane+albite+phengite+chlorite+epidote+titanite, glaucophane+albite±actinolite+chlorite+epidote+titanite which record a peak blueschist phase, a greenschist phase. Calculated pseudosection in the system Na₂O-CaO-FeO-MgO-Al₂O₃-SiO₂-H₂O-O yielded pressure conditions of around 0.95 GPa, 0.40 GPa, respectively.