Dendrobium candidum is a perennial epiphytic herb of Orchidaceae. Born on semi-humid rocks in mountainous areas at an altitude of 1600 meters, he likes warm and humid climate and semi-cloudy and semi-sunny environment, and is not cold-resistant. Generally can withstand the low temperature of -5℃. Dendrobium can be divided into dozens of species such as yellow grass, golden hairpin and whip. Dendrobium candidum is the best in Dendrobium candidum, named after its iron-green skin. Dendrobium candidum has unique medicinal value, and its stem is used as medicine. Dendrobium officinale, a traditional Chinese medicine, belongs to yin-tonifying drugs: benefiting stomach, promoting fluid production, nourishing yin and clearing heat. The tender stems of a few varieties can also be specially treated, twisted into a spiral or spring shape and dried. The trade name is Dendrobium candidum, also known as Fengdou. The only Dendrobium officinale approved by AQSIQ to protect geographical indication products are Dendrobium officinale in Huoshan County, Anhui Province and Dendrobium officinale in Tianmu Mountain, Lin 'an, Zhejiang Province.