The southern margin of the Shangnan—Danfeng (ShangDan) tectonic belt is composed of a series of tectonostratigraphic sheets, consisting of metamorphic sandstone, mica schist, garnetbearing mica—quartz schist, phyllonite and mylonite. Thrust—nappe systems, folds and faults are well developed in this area. They retain a large number of information about deformation and metmorphsim. In this paper, the garnetbearing mica—quartz schist is taken as the research object. According to the study on its detailed mineralogy and electronic microprobe analysis, it is proved that the garnet is almandine and has compositional zonation. The garnet—biotite geothermometer and geobarometry of Si in phengite are used to estimate the peak metamorphic temperature. The calculated metamorphic temperature is 560~588℃ and the upper limit of pressure is 0.59~0.65GPa. This metamorphic event mainly corresponds to epidote — amphibolite facies to low amphibolite facies and that is similar to the environment of continental orogenic belt. Deformation intensity analysis shows a strong deformation of rocks in this area, and the strain ellipsoid is flatellipsoidal (flattening). The paleostress calculated with the dynamically recrystallized quartz grain size in mylonites within the ShangDan ductile shear zone is to be 23.93～36.70MPa and the paleostrain rate is from 4.47793×10-15s-1 to 1.36090×10-14s-1,which belongs to medium strain rate.