Abstract: In order to explore the effect of the compound probiotic powder of Lactobacillus rhamnosus and Bifidobacterium lactis on the immunity of mice and its food safety. In this study, low, medium and high doses (1.00, 0.67, 0.34g/kg BW) of compound probiotic powder were orally administered to mice to observe the organ/weight ratio, cellular immune function, humoral immune function, monocyte-macrophage function, NK cell activity and other indicators, comprehensively evaluate the effect of compound probiotic powder on the immune function of mice for 30 d. In addition, rat acute toxicity test, genetic toxicity test (mouse bone marrow cell micronucleus test, mouse sperm deformity test, Ames test) and 30-day feeding test for rats were used for food safety research. The results showed that, compared with the negative control group, the high-dose group mice had significantly increased delayed-type hypersensitivity (DTH), antibody cell production (PFC), serum hemolysin levels, and the phagocytosis index of carbon clearance in mice (P<0.05), the carbon clearance and phagocytosis index of mice in the middle-dose group also increased significantly(P<0.05), but the low-dose group did not show a significant difference. In addition, the results of the mouse bone marrow cell micronucleus test, the mouse sperm abnormality test, and the Ames test were all negative. In the rat feeding test for 30 days, the test dose was in the range of 0.84~3.34 g/kg BW, and the growth of the rat was well developed, there was no significant difference in each index compared with the solvent control group (P>0.05). The growth and development of rats were good, and there was no significant difference in each index compared with the solvent control group (P>0.05). Therefore, the compound probiotic powder of Lactobacillus rhamnosus and Bifidobacterium lactis could enhance immunity without acute toxicity, genetic toxicity and subacute toxicity, and had high edible safety.