Abstract: To study the optimal conditions of banana oligosaccharide on the proliferation of Lactobacillus Rhamnus.Using banana oilgosaccharides as carbon source, the quantity of Lactobacillus Rhamnus as the measure, based on the single-factor experiment, the effect of culture time, additive amount of banana oligosaccharides, initial bacterial concentration and pH of basic medium was studied by the response surface methodology (RSM).Regression model between the quantity of Lactobacillus rhamnus and the four factors was built.Results showed that banana oligosaccharides as carbon source, the optimal conditions of Lactobacillus rhamnus proliferation was achieved as follows:Culture time of 37 h, additive amount of banana oligosaccharides of 6 g/L, bacterial concentration of 2.2×10⁶ CFU/mL, pH of basic medium of 6.80. Under this condition, three times repeated experiments were carried out, the actual measured number of Lactobacillus rhamnosus was 1.5×10⁹ CFU/mL, and the logarithm was 9.1706, the predicted RSD value was 0.149%.In summary, this experimental model was suitable, the regression equation has good fitting fitness, and the optimal optimization condition is suitable for the proliferation of Lactobacillus rhamnosus.