There are few studies on alveolar epithelial cells and HDACs in ALI, here, we still found the promoting effect of some HDACs such as HDAC1, HDAC2, and HDAC3 on EMT in ALI and the inhibiting effect of HDACis on EMT in ALI, which can eventually play a protective role against lung injury transformed into lung fibrosis. This evidence concerns the gene HDAC3 and pulmonary fibrosis.