A DNA microarray for detecting processed medicinal Dendrobium species (Herba Dendrobii) was constructed by incorporating the ITS1-5.8S-ITS2 sequences of 16 Dendrobium species on a glass slide. Using fluorescence-labeled ITS2 sequences as probes, distinctive signals were obtained for the five medicinal Dendrobium species listed in the Chinese Pharmacopoeia. The established microarray was able to detect the presence of D. nobile in a Chinese medicinal formulation containing nine herbal components.