The invention relates to an application of a tetraphenyl ethylene derivative in preparation of an antibacterial agent. The tetraphenyl ethylene derivative has a tetraphenyl ethylene structure with a substituent group on at least one benzene ring, can resist multidrug-resistant bacteria, especially can also resist planktonic bacteria and biofilm bacteria, can be used for effectively eliminating a biofilm, is low in cytotoxicity, has no hemolysis side effect, can be used for curing an animal model infected by common bacteria and multidrug-resistant bacteria and has a broad application prospect in the field of preparation of antibacterial agents.