Ninety 28-day-old weaned piglets were divided randomly into 5 groups. In blank control group, piglets were fed with basal diet; in positive control group (0.5% SC group), piglets were fed with basal diet supplemented with 0.5% Schisandra chinensis (S. chinensis); in 0.1%, 0.3% and 0.5% FSD groups, piglets were fed with basal diet respectively supplemented with 0.1%, 0.3%, 0.5% fermentated dregs of Schisandra chinensis. Diarrhea and feed intake data of piglets from the 5 groups were recorded for calculation of diarrhea rate and feed conversion ratio. Tissues from the middle part of duodenum, jejunum and ileum and jejunum mucosal of piglets from the control group, 0.5% SC group and 0.5% FSD group were collected 7, 14 and 21 days post-experiment for determination of the villus height, crypt depth, the number of intestinal epithelium cells and goblet cells and content of SIgA. The results showed that the diarrhea rate of 0.1% FSD group, 0.3% FSD group and 0.5% FSD group were respectively 13.87%, 30.82% and 41.72% lower than that of the control group; the FCR of 0.1% FSD group, 0.3% FSD group and 0.5% FSD group were respectively 1.7%, 4.02%, 8.6% lower than that of the control group. Compared to the control group, intestine villus of piglets from 0.5% SC group and 0.5% FSD group was complete；the villus height of duodenum, jejunum and ileum in piglets from 0.5% FSD group increased (P<0.05) while the crypt depth decreased (P<0.05), and the ratio of villus height to crypt depth was increased. The number of goblet cells and lymphocyte cells were higher, and the SIgA levels were extremely higher (P<0.01) in intestine of piglets from 0.5% FSD group compared with the control group. And there had no significant difference in indexes mentioned above between 0.5% SC group and 0.5% FSD group.