Disclosed herein is the use of TRAP per se as an active ingredient for the manufacture of a medicament for the treatment of Staphylococcus aureus infection. An exogenous TRAP (native TRAP or recombinant TRAP) per se can effectively inhibit the production of Staphylococcus aureus exotoxins, thereby reducing the pathogenicity of Staphylococcus aureus. In addition, a medicament including TRAP also stimulates the production of corresponding antibodies in human body at the time when it is used to treat Staphylococcus aureus infections, and these antibodies can further inhibit the production of Staphylococcus aureus exotoxins. Such double actions increase the effects of medicament and provide a novel medicament action mode. Moreover, since TRAP functions merely to the toxicity of bacteria but does not affect the growth of bacteria, it cannot make bacteria readily develop drug resistance, and also effective to drug resistant Staphylococcus aureus. Moreover, no homologous sequence of the TRAP proteins is found in human genome, so that the medicaments of TRAP cannot cause human immunologic diseases.