A strain of Lacbobacillus fermentum， L. Fermentum 733 with high yield of AI-2 signaling molecule was selected by our research group as the research object. Ultraviolet spectrophotometry， chemiluminescence and crystal violet staining were used. The effects of different concentrations of Mg2+， Mn2+， Ca2+， Fe3+ and Na+ on the growth of L. fermentum 733， biofilm production and the activity of signal molecule AI-2 were investigated. The results showed that when the concentration of Mn2+ was 0.15 mg/mL， the growth amount and biofilm yield of L. fermentum 733 were the largest， the growth density reached an OD595nm value of 2.264±0.015， while the biofilm formation achieved an OD595nm value of 1.116±0.007. When the concentration of Ca2+ was 0.1 mg/mL， the activity of L. Fermentum 733 signal molecule AI-2 was the highest， and its relative fluorescence intensity was 98.874±5.703. Combining Mn2+ and Ca2+ to explore their effects on cell growth， biofilm and signal molecule AI-2， and to observe the structure and morphology of cell biofilm， it is concluded that the combination of Ca2+ and Mn2+ can increase cell growth， biofilm production and signal molecule AI-2 activity， and Ca2+ can increase the aggregation degree of biofilm. In summary， different metal ions have different effects on bacterial growth， signaling molecule AI-2 and biofilm， which lays a theoretical foundation and data support for exploring bacterial quorum sensing.