Abstract: The recent advances in synergism of cadherin fragments to Bacillus thuringiensis (Bt) Cry toxins were reviewed.Cadherin receptors mediated virulence of the Cry toxins to insect pests.The molecular interaction between cadherin extracellular repeats or membrane proximal domain and Cry toxins involved in several active sites.Some unfolding fragments of cadherins could facilitate the formation of Bt Cry toxin oligomers,and consequently exhibited synergistic effects on Bt Cry toxins to target pests.This discovery provides novel strategies to enhance the insecticidal activity of Bt Cry toxins,and to overcome the resistance of insects to Bt toxin-based bio-pesticides or transgenic crops.