Transgenic cotton has been widely cultivated internationally since 1996, which created a huge social, economic and environmental benefit. To date, forty transgenic cotton events have been permitted to commercialization. In our country, the insect-resistant cotton is the first commercial planted transgenic crop in a large scale. Meanwhile, the study of gene flow from transgenic cotton has been conducted in USA, Australia and China. According to the data accumulated in recent decade, the distance of gene flow at a threshold value of 0.1% is 70 m.