The microarea compositional variations of garnet, plagioclase and biotite in Zhoutan Group show obvious regularity. Garnet displays typical growth zoning, which reflects the crystallization and growing process of garnet. The contact edge compositions of the coexisting Grt, Bi and Pl should reflect the temperature and pressure of the peak metamorphic stage. On the basis of garnet zoning and Grt-Bi geothermometry as well as GASP barometry, it is known that the pattern of the metamorphic pT paths is of the clockwise type, and that metamorphism must have taken place in the tectonic environment of continental collision zone.