The geography of the Sanctuary area is Mountainous, consisting steep to very steep and rugged terrain. The altitude varies from 1800 to 5000 M. The Eastern part of the Himalayas consists of Eastern Tibet, the Yamana province of South China, Hainan the Northern part of the Indo-China, Burma and northern part of Thailand. These constitute a single natural unit of mountainous land and known as Indo-China sub-region. During summer season the coverage temperature varies form 18®C to 22®C and heavy snowfall (6m to 10m) is very common in winter.
The vegetation of Dibang Wildlife Sanctuary is of temperate and alpine type. The composition of flora depends mainly on the locality factor i.e. climatic, Topographic, Edaphic and biotic factors. The Vegetation can be broadly placed as a. Temperate broad leaved forests (1800m to 2800m) b. Temperate conifer forests (2800m to 3500 m).
The Sanctuary is very rich in animal population. The herbivores found are Goral, Takin, Serow and Musk Deer. Migration of population takes place due to food crises during seasonal variation. Among this carnivores are snow leopards in high altitudes and clouded leopard in the lower latitudinal zone found here. There is enough scope for the development of tourism complex by providing certain facilities like eco-friendly tourist cottages, Trekking path from Anini to valley of flower of total distance of 60 km, providing transit camp at 5 Km interval along the trekking path, transport and Forest Rest House. The Sanctuary is near Indo-China boundary towards Dambing outpost. There is a beautiful lake called as Kahai white means lake in the middle of the flower valley. The flowering season of this valley is during the month of May and June.