Abstract: Effect of adding different concentrations astragalus liquid on growth and enzyme production ability of Lactobacillus acidophilus were studied.Two sample of Lactobacillus acidophilus were analyzed by adding and not adding astragalus liquid in the modified MRS medium and compared by biomass and growth cycle.Meanwhile the activity of β - galactosidase, glucose oxidase and α - amylase produced by Lactobacillus acidophilus were measured. The best adding concentration of astragalus liquid was conformed. The results showed that the concentration of adding astragalus liquid was 0.032mg /mL in the modified MRS medium could obviously promote Lactobacillus acidophilus proliferation, and in this concentration, pH was 3.88.When the concentration of astragalus liquid was 0.016mg /mL, the activity of β - galactosidase, glucose oxidase and α - amylase produced by Lactobacillus acidophilus were maximum value, which were 387.56, 14.42, 4.4U.