Effect of steroidal saponins fromFructus tribuli on growth of Bifidobacterium bifidum BB01, BB03 and Lactobacillus acidophilus LA09 was studied by measuring optical density at 600nm (OD600) and pH using MRS media as the control. The concentration of steroidal saponins (w/v) added in was 0.05%, 0.10%, 0.15%, 0.20% and 0.25%. Results were as follows: addition of steroidal saponins could improve the buffer ability of MRS and promote the growth of Bifidobacterium bifidum BB01 and BB03. The optimum concentration of nutrient supplement in MRS media was 0.20% at incubation 24h for Bifidobacterium bifidum BB01 and 0.25% at incubation 24h for Bifidobacterium bifidum BB03. Addition of steroidal saponins on Lactobacillus acidophilus LA09 didn’t play an obvious role in promoting growth when it was in high level.