This experiment was conducted to study the effects of different lactic acid bacteria on intestinal flora, morphological structure, pH and immune organ index of Zi geese. Ninety 28 d old healthy Zi geese were randomly divided into three groups with three replicates in each group, with ten geese in each replicate. Geese in the control group were fed a basal diet, and the experimental groups were fed the basal diet supplemented with 10⁹ CFU/kg Lactobacillus plantarum (ordinary lactic acid bacteria, group I) and 10⁹ CFU/kg Pediococcus acidilactici B2 (isolated lactic acid bacteria, group II), respectively. The experiment lasted for 28 days. The results showed as follows: (1) The number of lactic acid bacteria in cecum of Zi geese in group II was higher than that in group I and control group (P<0.01), and the number of Escherichia coli and Salmonella in cecum of Zi geese in group II was lower than in the control group (P<0.05). (2) The villus height of jejunum in group II was higher than that in the control group (P<0.05), the crypt depth was lower than that in the control group (P<0.05), and the villus height/crypt depth was higher than that in group I and the control group (P<0.01). The villus height/crypt depth of jejunum in group I was higher than that in the control group (P<0.05). The villus height and crypt depth of ileum in group II were higher than those in group I and the control group (P<0.05). (3) The pH of jejunum in group II was lower than that in the control group (P<0.05). (4) The thymus, bursa of fabricius and spleen index of group II were higher than those of the control group (P<0.05). It can be seen that the addition of isolated P. acidilactici B2 in the diet can maintain the balance of intestinal flora, improve the intestinal morphology and improve the immunity of Zi geese, and the effect is better than that of ordinary L. plantarum.