Abstract: Using of quorum-sensing inhibitors to target the quorum-sensing system(QS)of pathogenic bacteria to reduce pathogenicity had become a breakthrough in effective control. The growth and AI-2 activities of L. m were investigated under different concentrations of DMHF by measuring the concentration of bacteria and the luminescence of reporter bacteria Vibrio harveyi BB170;The interference effects of DMHF on AI-2 system of L. m were evaluatied by detecting the dynamics,biomembranes and hemolysis test of L. m by semi-solid puncture,crystal violet and hemolytic plate method. The results showed that DMHF of ≤ 200 μg/mL had no effect on the growth of L. m,but significantly inhibited the activity of AI-2 system,the AI-2 activity value of the experimental groups was all lower than 40% of the negative control group,and thus it could be determined that DMHF was an inhibitor of AI-2 system;100 μg/mL of DMHF could significantly inhibit the motor ability of L. m;The inhibitting rates of biofilm formation of L. m were 29.72%,44.88% and 75.27% at the concentration of 50,100 and 200 μg/mL of DMHF,respectively. 200 μg/mL of DMHF completely inhibited the formation of hemolytic rings. This study provided basis for the use of DMHF as an inhibitor of AI-2 system.