Abstract: E. coli K88 is the main pathogen of post-weaning diarrhea (PWD). The existing commercial vaccines could effectively control diarrhea caused by E. coli in newborn piglets from immuning sow, while it was unlikely effective to PWD. Oral vaccine could induce antibodies produced in local mucosal, prevent E. coli adhere to intestinal epithelium, thereby prevent PWD. To study the biological characteristics of K88 and its receptors at molecular level was important to develop oral vaccine. The progresses in the basic characteristics, protein subunits and receptors of K88 fimbriae at home and abroad were decribed, furthermore, the application prospect of engineering bacteria vaccine and plant-based vaccine were discussed．

Key words: post-weaning diarrhea, enterotoxigenic E.coli, K88, fimbriae