Platelet activation plays an important role in the occurrence and development of sepsis. During sepsis stage, platelet activation can cause endothelial cell damage, promote the formation of neutrophil extracellular traps (NETs) and microthrombosis, aggravate coagulation dysfunction and inflammatory response disorder, and ultimately lead to multiple organ dysfunction syndrome(MODS) in septic patients. During the infection, platelets also participate in the process of congenital immune response and acquired immune response, through the interaction with immune mediators, platelets can actively defend the invasion and spread of pathogens, but also may aggravate the disease and even cause septic shock due to overactive immune response. This paper mainly introduces the role of platelet activation in the occurrence and development of sepsis, and highlights the role of platelet-mediated immune response in anti-infection of human body.