Archean metamorphic strata are widely distributed in Miyun and Huairou District in the northern mountainous area of Beijing. This area has experienced multi-stage geological tectonism and produced abundant mineral resources, and thus aroused much interest among geological experts both in China and abroad. This paper puts forward a new classification scheme of the metamorphic strata and the supracrustal rock on the basis of deeply and systematically studying Archean metamorphic formation, metamorphic conditions, deformation and metamorphism, isotope chronology and some other aspects, thus raising the research level of metamorphic rocks to a new height.