Sichuan Province of southwest China, is located in the upper reaches of the Yangtze River, between eastlongitude 92°21' to 108°12' and between north latitude26°03 ' to 34°19', 1,075 km from its east to west, and over 900 km from its north to south. It neighbors Hunan and Hubei to east, Yunnan, Guizhou to south, Tibet to west, Qinghai, Gansu and Shaanxi provinces to north. Sichuan covers the area of 486,000 square kilometers, ranking fifth in the country,after Xinjiang, Tibet, Inner Mongolia and Qinghai.

　　The topography over the whole province differs enormously from east to west with complex and various terrains. The terrain of China’s mainland forms a flight of three steps in terms of altitude. Sichuan lies between the first step, namely Qinghai-Tibet Plateau and the second step, namely the Middle-lower Yangtze Plain. It is high in the west while low in the east, demonstrating a distinct disparity in altitude. Plateaus and mountainous regions can be seen in west Sichuan at altitudes above over 4,000 meters, while basins and hilly areas can be found in the east, at altitudes above 1,000 to 3,000 meters. The whole province can be divided into three major parts: the Sichuan Basin, the SichuanNorthwest Plateau and the Sichuan Southwest Mountains.

　　The Sichuan Basin, covering an area of 165,000 square km, is one of the four largest in the country.This Basin is surrounded by mountainous regions, having the Qinling Mountains in the north, Micang Mountain, Daba Mountain in the east, the Dalou Mountain in the south, and Longmen Mountain, Qionglai Mountains in the northwest. The regional climate is warm and humid, warm in winter and hot in summer, most areas with annual rainfall of 900 to 1200 mm. Sichuan enjoys a subtropical humid monsoon climate and its vegetation is subtropical evergreen broadleaf forest. The pattern of agricultural use is double cropping in a year. The west are of Sichuan Basin is Chuanxi Plain which is the irrigation area of Dujiangyan. The lands in West Sichuan Plain are fertile and with high productivity. The middle of Sichuan Basin is purple hill area, 400 to 800 meters above sea level, whose terrain is slightly tilted to the south. Minjiang River, Tuojiang River, Fujiang River, Jialing River run to south through its north mountains and join Yangtze River. Besides, the east of Sichuan Basin is East Sichuan Parallel Range Gorge Region, including Huaying Mountain, Tongluo Mountain, and Mingyue Mountain.

　　The northwest of Sichuan Province is Northwest Sichuan Plateau, belonging to the southeast corner of Tibetan Plateau, average elevation of 3,000 to 5,000 meters, alpine climate, covered with alpine meadow vegetation.

　　The southwest of Sichuan Province is the north section of Hengduan Mountains with high mountains and stiff valleys. Rivers flow through mountains alternatively. The rivers and mountains are from east to west Minshan Mountain, Minjiang River, Qionglai Mountain, Dadu River, Daxue Mountain, Yalong River, Shualuli Mountain and Jinsha River. The climate and vegetation here are in vertical distribution, mainly including boreal coniferous forests, temperate mixed broadleaf-conifer forests, northern subtropical mixed evergreen and deciduous forests, and middle subtropical mixed evergreen and broadleaf forests.