The Nanyi Ditch Scenic Spot is located in the south of Mailing county of Nyingchi prefecture. The ecological environment is well persevered, with humid climate and rich wildlife resources. With an average altitude of 2,500 meters, it is known as “the highest secret green land on earth”. It is also the birthland of Tibetan medicine, and it is said the earliest ancestor of the Tibetan medicine used to be here, practicing medicine and imparting knowledge.