Mechanical ventilation is not only an important treatment method of acute respiratory distress syndrome (ARDS),but also one of the basic treatments in the intensive care unit (ICU).However,mechanical ventilation itself can cause or aggravate acute lung injury,which is called ventilator-induced lung injury (VILI).Currently,clinical pathogenesis of VILI includes four categories such as barotrauma,volutrauma,atelectrauma and hiotrauma.The pathogenesis of mechanical injury has been widely accepted,but the biological injury pathogenesis is unclear.With further research,we found that in the late stage VILI patients occured proliferation of puhnonary fibrosis,which may be formed by partial epithelial-mesenchymal transdifferentiation (EMT).Further study of specific pathogenesis of biotrauma and ARDS pulmonary fibrosis proliferation could provide new ideas for the clinical treatment of VILI.