Abstract: After treating with Bifidobacterium on spleen-deficiency mice, the quantities of main bacteria in colonic contents and feces of mice such as Enterobacteriaceae, Enterococcus, Bifidobacterium, Bacterocdaceae and Lactobacillus were detected. Results showed that Result: the quantities of Bacterocdaceae and enterococcus microbiota in spleen-deficiency mice were increased (P＜0.05). However, bifidobacteria and Lactobacillus were decreased (P＜0.01). After treating with Bifidobacterium 6d~12d, the quantities of Bacterocdaceae and enterococcus microbiota in spleen-deficiency mice were decreased (P＜0.05). However, bifidobacteria and Lactobacillus were increased (P＜0.01). Observation of histology in colorectal indicated thickness of the intestine muscle layer and quantity of the cup cell was increased and villi interstinales arrange order on intestines mucous membrane was become better.