Oreorchis yachangensis, a new species of Orchidaceae from Yachang Orchid National Nature Reserve, Guangxi, China, is described and illustrated. The new species most closely resembles Oreorchis patens in having samll flowers, yellow sepals and petals, both the petals and the lip with purple spots, but is distinguished from O. patens and the other species in Oreorchis by having lip oblong, mid-lobe 2-lobed. O. yachangensis is restricted to a wet valley in Yachang Orchid National Nature Reserve, southern China.