Abstract: Objective:The growth curve,acid production rate,acid and bile salt resistance of Lactobacillus plantarum KLDS 1.0318 and its possible immunomodulation function in vitro were studied. Methods:The growth curve of the strain was determined by plate count method and UV visible spectrophotometry,and its acid producing capacity was determined by pH meter,the viabiblity of the strain during exposure to acid and bile salt MRS broth measured by plate count method. CCK-8 method was used to observe the effects of different doses of the strain on the proliferation of mouse spleen lymphocytes and the level of energy metabolism,and its effect on phagocytosis of macrophages were evaluated by the method of macrophage phagocytosis of neutral red. Results:The strain reached a logarithmic phase after 4 h and a stable period after 12 h. It had a stronger ability of acid production,the pH dropped to 4.16 at 12 h. The survival rates of the strain were 91.20% at pH2.5 and 97.50% at pH3.5 after 3 h of culture,respectively. After being cultured for 4 h at a bile salt concentration of 0.3 and 0.5 g/100 mL,the survival rates of the strain were 95.40% and 87.76%,respectively. A certain dose of Lactobacillus plantarum KLDS 1.0318 could promote the activity of splenic lymphocytes and macrophages and the promoting effect was dose-dependent. Conclusion:Lactobacillus plantarum KLDS 1.0318 grew fast,had strong acid producing ability,acid resistance,bile salt tolerance,and potential immunomodulatory function.