Changning County, which belongs to Yibin City, Sichuan Province, is located in the southern edge of Sichuan Basin, in the center of Yibin, with east longitude104 44' 22 "~105 03' 30" and north latitude 2815'18 "~ 28". Changning county has small north and south ends and large upper abdomen. The terrain is high in the south and low in the north, with low mountains in the south and hills in the north-central part, covering an area of 94 1.7 1 km2. The terrain is high in the south and low in the north, with an altitude of 245.9 m-1408.5 m. The forest coverage rate is 62.8%, and the highest content of negative oxygen ions in the air can reach 47,000 /cm3 (Qidonggou). It is a famous hometown of longevity.