Abstract:Bt-transgenic crops are the new generation plant protection products, which play a great role in integrated pest management. It is a common fact that the Bt-transgenic crops possess high resistance to pests and increase the economic benefits. However, the expression of Bt toxins in Bt crops at a high level during the entire growing season may lead to resistance evolution. Plutella xylostella (Linnaeus) is the only one insect that has evolved resistance to Bt in the field. Many insect species selected under laboratory conditions have evolved resistance to Bt toxin. The mechanisms of resistance evolution reported are related to the alteration of binding Bt toxin to the receptor in midgut membranes and the changes in midgut proteolytic activity of the Bt toxin. The mechanisms of resistance may be correlated with many other factors. Although a series of resistance management strategies such as the high-dose/refuge and multiple toxins have been effective. It is desiderated to solve for further understanding of resistance mechanisms and improving resistance management strategies to ensure Bt-transgenic crops long-term sustainability and maximize their benefits.