Acute lung injury（ALI） and acute respiratory distress syndrome（ARDS） are life-threatening clinical syndromes in the in－tensive care unit. At present，ARDS mortality rate remains high（>40%）. Its treatment and the use of biological markers for early di－agnosis are still major problems in the field of critical care medicine. High mobility group box-1 protein（HMGB1） has recently been identified as a new proinflammatory cytokine and late mediator of inflammation. It is associated with sepsis，cancer，autoimmune dis－eases and many other diseases. HMGB1 is an alarmin its concentration can reflect the severity of the inflammatory and tissue injury，and is closely related with the prognosis of the disease. Antagonizing HMGB1 can block the cascade of inflammatory pathways，which may provide a new therapeutic target for the treatment of ARDS.In this paper，we reviewed on the role of HMGB1 in ALI/ARDS.