Abstract: Two trials were conducted to study Glucagon-like peptide 2 secretion in postweaning piglets and the effect of immune challenge on gut development and GLP-2 level. The first trial indicated that the GLP-2 level was reduced by the weaning anorexia, and then tended to recover with the increased feed intake. The second trial showed that the immune system was activated by the immune challenge, the feed intake (P<0.01), GLP-2 level (P<0.05), the villus height/crypt depth (P<0.05) were also decreased, while the mucosa lactase and sucrase activity, goblet cells tended to be decreased. The results indicate that immune challenge resulted in the anorexia and immune system activation, which trigger the decreased GLP-2 that may influence gut development.