Bacterial infections caused by pathogenic bacteria are extremely threatening to human health. Currently, the treatment of bacterial infections relies heavily on antibiotics, leading to a high incidence of antibiotic abuse. Bacterial resistance appeared along with the misuse of antibiotics that produced growing harm to human beings. Therefore, a cutting-edge strategy for treating bacterial infections is indeed needed. Here we prepared QCuRCDs@BMoS2 nanocomposites (QBs) for an efficient bacterial trapping and triple quaternary ammonium salt/photothermal/photodynamic bactericidal method. Copper-doped carbon quantum dots were first prepared by using a solvothermal method, modified with quaternary ammonium salts, and then combined with grafted MoS2 nanoflowers. The long alkyl chains of QBs and the sharp surface of MoS2 facilitate the destruction of bacterial structures, while the electrostatic adsorption binds closely to bacteria, shortening the bactericidal distance of the reactive oxygen species (ROS). Moreover, the excellent photothermal performance under 808 nm irradiation in the near-infrared (NIR) region and deep penetrating heat can accelerate oxidative stress and achieve a multisynergistic bactericidal purpose. Consequently, QBs with ideal antibacterial properties and inherent brightness hold great promise in the biomedical field.