Sepsis is a life-threatening organ dysfunction caused by an imbalance in the response to infection. Clinically the effects of anti-infection and fluid resuscitation are limited, and the morbidity and mortality of sepsis are still high. Interleukin-33 (IL-33), a member of the IL-1 family, binds to various cell types through the ST2-IL-1 receptor helper protein complex. IL-33 and its receptor ST2 play an important role as immune regulatory factors in sepsis. This article reviews the pathophysiological characteristics of sepsis, the biological characteristics of IL-33 and its receptor ST2, and the relationship between IL-33/ST2 and sepsis, so as to provide new ideas for the diagnosis and treatment of sepsis.