Because the cotton bollworm is the main pest in cotton production, the cotton yield is reduced by 10%- 15% in general years. Since 1990, Helicoverpa armigera broke out year after year in China, with an area of 4.33× 106hm only in 1992, resulting in a loss of more than 30% of China's total cotton output, more than 50% in serious areas and a direct economic loss of more than RMB1000 billion. In recent years, the generation use of highly toxic chemical pesticides has not only increased the cost of cotton planting, but also destroyed the ecological environment. At the same time, the resistance of Helicoverpa armigera is also obviously enhanced, which increases the difficulty of pest control and seriously hinders the sustainable development of cotton production. In order to solve the worldwide problem that restricts the stable development of cotton production, the breeding research of transgenic insect-resistant cotton has been carried out by combining bioengineering technology with conventional breeding at home and abroad. At the end of 1988, Monsanto obtained Bt transgenic cotton. 1At the end of 1995, the US Department of Agriculture (USDA), the US Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) successively approved the large-scale promotion and utilization of Bt transgenic cotton in domestic production. From 65438 to 0997, the Ministry of Agriculture of China approved the release of transgenic insect-resistant cotton in five provinces (autonomous regions) of Hebei, Henan, Jiangsu, Xinjiang and Liaoning, and commercialized it in four provinces of Shandong, Shanxi, Anhui and Hubei. In 2002, the global cotton area was 34 million hm, of which 20% or 6.8 million hm was planted with transgenic cotton, and 2.4 million hm was planted with monovalent Bt gene. The planting area of transgenic cotton is second only to soybean (36.5 million hm) and corn (12.4 million hm). The planting area of transgenic crops in China is 200,000 hm (4%), which is 40% higher than 200 1 year. They are basically Bt transgenic cotton, accounting for 5 10/00000 hm of cotton planting area in China. Since 1997, the annual planting area of transgenic Bt cotton in Xinjiang is about 700,000 mu, mainly concentrated in Korla, Bayinguoleng Mongolian Autonomous Prefecture and Hami area in southern Xinjiang.