The overuse of antibiotics has caused the emergence of drug-resistant bacteria and even superbugs, which makes it imperative to develop promising antibiotic-free alternatives. Herein, a multimodal antibacterial nanoplatform of two dimensional/two dimensional (2D/2D) mesoporous Co3O4/BiOCl nanocomposite is constructed, which possesses the effect of “kill three birds with one stone”: (1) the use of mesoporous Co3O4 can enlarge the surface area of the nanocomposite and promote the adsorption of bacteria; (2) Co3O4 displays remarkable full-spectrum absorption and photo-induced self-heating effect, which can raise the temperature of Co3O4/BiOCl and help to kill bacteria; (3) the p-type Co3O4 and n-type BiOCl form a p-n heterojunction, which promotes the separation of photoelectrons and holes, thus producing more reactive oxygen species (ROS) for killing bacteria. The synergism of mesoporous structure, photothermal effect and photocatalytic ROS makes the developed Co3O4/BiOCl a promising antibacterial material, which shows outstanding antibacterial activity with an inhibition rate of nearly 100 % against Escherichia coli (E. coli) within 8 min. This work provides inspiration for designing multimodal synergistic nanoplatform for antibacterial applications.