Abstract: Effects of insectresistant transgenic cotton on soil nutrients and enzyme activities were studied after planting insectresistant transgenic cotton for 5 and 10 years. The results revealed that there were no significant differences for soil organic matter, total nitrogen, hydrolysable nitrogen and available phosphorus between soil planting with insectresistant transgenic cotton and that with nontransgenic cotton, but soil available potassium increased. Compared with soil planting with nontransgenic cotton, soil dehydrogenase activity significantly increased after 5 years,and soil catalase activity also significantly increased after 10 years planting with transgenic cotton. In the collection period of insectresistant transgenic cotton, soil total nitrogen and available potassium decreased, by contrast,soil pH and organic matter increased.