Abstract: The orthopyroxenes of granulite facies in Miyun region,Beijing,are hypersthenes,the end members of which are Wo 4% En 52—59%,Fs 37—44%,and ferrous index 38.8—45.5%; while the clinopyroxenes in pyroxene granulite and hornblende granulit ubfacies are augites with end members of Wo 41—43%,En 39—43%,Fs 14—20%,and ferrous index 30.8—34.4%.According to Saxana's two pyroxenes geothermometer method,it has been calculated that metamorphism temperature in this region is 702—887℃,while the pressure 9—10Kb.