OBJECTIVE： To study the tonifying spl een effect of Codonopsis pilosula polysaccharides （CPP） on spleen-deficiency model mice. METHODS ：Totally 60 ICR male mice were randomized into blank group ，model group ，CPP high-dose，medium-dose and low-dose groups [ 1.6，0.8，0.4 g/（kg·d）]，Sijunzi tang （SJZT）group [ 30 g/（kg·d），by crude drug] ， with 10 mice in each group. Except for blank group ，other groups were given Sennae Folium solution intragastrically （0.4 g/d）to establish spleen-deficiency model. After modeling ，administration groups were given relevant drug intragastrically ，and blank group and model group were given 20 mL/kg normal saline intragastrically ，once a day ，for consecutive 6 weeks. After last administration，body weight of mice in each group was measured and their general behavioral characteristics were observed. The red blood cell count in whole blood were recorded ，and the contents of D-xylose，gastrin（GAS），motilin（MTL），somatostatin （SS），vasoactive intestinal peptide （VIP），amylase（AMS），immunoglobulin（IgG and IgM ）and lipopolysaccharide （LPS）in serum were determined ；mRNA and protein expressions of Claudin and Occludin in colon tissues of mice were also detected. RESULTS：Compared with blank group ，body weight of mice in model group was significantly decreased （P＜0.05），and the spleen deficiency symptoms such as sparse back hair and no luster appeared ；the red blood cell count in whole blood ，serum contents of D-xylose，SS，VIP，AMS，IgG and IgM ，mRNA and protein expressions of Claudin and Occludin were significantly decreased（P＜0.05 or P＜0.01）；serum contents of GAS ，MTL and LPS were significantly increased （P＜0.01）. Compared with model group ，the body weight of mice were increased significantly in CPP high-dose group （P＜0.05），and spleen-deficiency symptom was improved significantly. Except for the serum contents of D-xylose and IgM ，the protein expressions of Claudin and Occludin in colon tissue had no statistical significance in CPP low-dose group （P＞0.05），above indexes of other groups w ere improved significantly （P＜0.05 or P＜0.01）. CONCLUSION ：CPP can i mprove spleen-defic iency model mice induced by Sennae Folium，the mechanism of which may be associated with regulating gastrointestinal hormone secretion ， enhancing immunity and protecting intestinal mucosal barrier.