Adhesin is a kind of bacterial surface components which directly involves the adhesion of bacteria and host cells,so it is called colonization factor.When they invade host tissue and cause host disease,adhesion is the first step to contact and infect the host epithelial cells,and then the pathogenic roles of adhesin attracted researchers' wide attention in the avian pathogenic E.coli.Here,adhesin composition,adhesive mechanism,molecular biological characteristics and the corresponding adhesion receptors of avian pathogenic E.coli's adhesin were reviewed,which would provide the theory to studying pathogenesis and immunoprophylaxis of colibacillosis.