To investigate the potential of walnut dietary fiber to promote the growth of Lactobacilli， various mass concentrations of dietary fiber (0.1 to 3.2 g/L) were added to MRS medium. The effects of walnut dietary fiber on the growth of ten strains of Lactobacilli were compared， and the optimal 'fiber + strain' combination was selected based on promotion rate to evaluate the proliferation effects. The results showed that walnut insoluble fiber only promoted the growth of Lactiplantibacillus plantarum by up to 9.95%， while inhibiting the growth of the other nine strains. In contrast， walnut soluble fiber exhibited the highest promotion rate for Ligilactobacillus salivarius at 44.34%， followed by Lactiplantibacillus plantarum (16.14%) and Lacticaseibacillus casei (11.23%). The effect of walnut soluble fiber on the proliferation of Ligilactobacillus salivarius were as follows: walnut soluble fiber significantly increased the biomass， viable count， non-specific adhesion ability (P<0.05). At a fiber concentration of 3.2 g/L， the biomass and viable count increased by 2.86 times and 7.28 times， respectively， and the surface hydrophobicity increased by 8.81%. Additionally， it significantly promoted the formation of biofilm (P<0.05)， increased sugar utilization， and reduced the pH value of the fermentation broth (P<0.05). At 3.2 g/L fiber addition， the pH value of the fermentation broth reached its lowest point at 3.74. Furthermore， walnut soluble fiber significantly increased the activities of β-galactosidase and lactate dehydrogenase in Ligilactobacillus salivarius (P<0.05). Conclusion: walnut soluble fiber promotes the proliferation of Ligilactobacillus salivarius by increasing the activities of β-galactosidase and lactate dehydrogenase， and is beneficial to promoting its adhesion and biofilm formation. These findings provide a theoretical reference for the use of walnut dietary fiber as a new type of prebiotics， and offer new ideas for its comprehensive development and utilization.