Abstract: Cymbidium aestivum Z.J.Liu et S.C.Chen,a new species of Orchidaceae from southern Yunnan,is described and illustrated.The new species is akin to Cymbidium dayanum Rchb.f.,from which it differs by the larger flowers with sepals 4.2-4.8 cm long,pale purple-brown sepals and petals,lanceolate bracts 1-1.5 cm long and a long mid-lobe equaling 3/5 the length of the lip.