Retrograded eclogites from Mengku area contains massive amphiboles, which formed in late period of the remetamorphic process. It could keep a record of petrogenetic information in the late remetamorphic period. Based on a study of systematic mineralogy, the authors identified three periods of amphiboles and furthermore divided them into ten types. They mostly belong to calcium amphiboles such as tschermakite, ferrotschermakite, magnesiohornblende, ferrohornblende, magnesiohastingsit, ferropargasite, tremolite and actinolite, with some sodic-calcium amphiboles such as barroisite and winchite. Studies show that the formation environment of amphiboles gradually changed from reduction through weak oxidation to oxidation in the remetamorphic process. The numerical values of temperatures and pressures were computed on the basis of electron microprobe data in this paper. Combined with petrographic data, three periods of retrograde metamorphism were recognized. The first period could be divided into two stages: the early was approximately isothermal and decompression process, p=0.56~0.75 GPa and t=642~709℃, forming ferropargasite and ferrotschermakite; the latter was an isothermal and decompression process, p=0.39~0.56 GPa and t=619~642℃, forming tschermakite. The second period was a cooling and decompression process, p=0.23~0.42 GPa and t=460~610℃, forming magnesiohornblende. The third period was a isothermal and decompression process, p=0.09~0.31 GPa and t=350~420℃, forming tremolite and actinolite. The composition variation of amphiboles indicates a gradual cooling and decompression process, in which retrograded eclogites moved from crust bottom (amphibole-eclogite facies-high pressure-granulite facies) to mid-upper crust (hornblende facies, green-schist facies). The process corresponded to Indosinian collision orogenesis, Yanshanian regional crustal extension and Himalayan intracontinental orogenesis in Changning-Menglian belt.