Abstract: Post-weaning diarrhea is a common and harmful stress disease in piglets. In order to investigate the relationship between intestinal mucin 12 and post-weaning diarrhea in piglets and to reveal the role of MUC12 in resisting post-weaning diarrhea, forty-eight 35-day-old Min piglets and 60 landrace piglets were divided into post-weaning diarrhea group, healthy weaning group and non-weaning group（control group）.The distribution and morphology of goblet cells in the intestine of piglets were investigated after slaughter, and the staining statistics of goblet cells in the duodenum, jejunum, ileum, cecum and colon were carried out. The relative expression of MUC12 mRNA in 5 intestinal segments was detected by qRT-PCR. The results showed that the goblet cells were stained purple and distributed in each intestinal segment and shown to be with the enlarged top and narrow and clear bottom.The coloredness of goblet cells of the duodenum and jejunum（P＜0.01） of Min piglets in unweaned group and of the duodenum（P＜0.05）, jejunum and ileum（P＜0.01）of Min piglets in weaned healthy group were higher than that in landrace piglets. MUC12 mRNA expression was found significant in cecum and colons, but slight in duodenum, jejunum and ileum in all pigs of groups, among which, MUC12 mRNA expression in jejunum, ileum and colon of Min piglets in unweaned group and in weaned healthy group was higher than that of Landrace piglets. It can be concluded that the higher intestinal expression of MUC12 in Min piglets than that of Landrace could be an important physiological factor for the lower incidence of post-weaning diarrhea in Min piglets than in landrace piglets.