The invention relates to application of a substitutive 2,3-didetonindoline compound in preparing bacterial infection preventing and/or treating medicines. Bacteria can be gram-positive bacteria, specifically, enterococcus faecalis and/or staphylococcus aureus. Pharmacodynamic tests show that the substitutive 2,3-didetonindoline compound has an obvious inhibiting function on virulence factors of the gram-positive bacteria, also has a regulating function on innate immune systems of caenorhabditis elegans, and can become a quite excellent candidate medicine for preventing and/or treating bacterial infection.