The probiotic potential of four Lactobacillus from breast-fed infants faeces： Lactobacillus rhamnosus BF-1， Lactobacillus plantarum BF-15， Lactobacillus salivarius BF-29 and Lactobacillus paracasei BF-55 was evaluated by a series of in vitro assays： resistance to simulated gastrointestinal juice and bile， adhesion to Caco-2 cells， the safety and the effect on proliferative capacity of the spleen lymphocytes in th-e mice. Results showed that it was indicated that： Lactobacillus plantarum BF-15 has stronger tolerance toartificial digestive juice and bile salts. The adhesion to Caco-2 cells [（7.10 ± 0.30）CFU/cell] of BF-15 was significantly higher than the positive control strain LGG [（3.90 ± 0.30） CFU/cell]（P＜0.05）. In addition， Lactobacillus plantarum BF-15 was resistant not only to aminoglycoside inherently，but also to oxacillin and cephalothin without plasmid. In a certain concentration range（1×106-107 CFU/mL）， viable or heat-killed Lactobacillus both could promote lymphocyte proliferation of the mice in vitro and showed a dose-dependent relationship. Under the same bacterium concentration， there was no significant difference in immunoregulation ability between the two strains （P>0.05）. Lactobacillus plantarum BF-15 presents favorable strain-specific properties， which could provide probiotic resources for developping new infants and young children formula milk powderin and new probiotic products in the future.