Objective To study the differences in gene expression in A549 cells transfected with Forkhead box protein O1(FOXO1),and provide clues to further exploring the mechanism of FOXO1 in acute lung injury. Methods After using TNF-α to stimulate A549 cells,the eukaryotic expression vector GV230-FOXO1 was transfected into A549 cells by using lipofectamine transfection reagent.The RNA was isolated and differentially expressed genes were screened with high-throughout DNA microarray. Results The eukaryotic expression vector GV230-FOXO1 was successfully constructed and verified.High quality mRNA was isolated and prepared for microarray screening,which passed RNA quality control.The DNA microarray data indicated that 317 genes were up-regulated and 237 genes were down-regulated in A549 cells transfected with FOXO1.The function of these differentially expressed genes involved in many aspects,such as proliferation,apoptosis and differentiation. Conclusions Differentially expressed genes in A549 cells transfected with FOXO1 can be successfully screened by using DNA microarray.FOXO1 may influence the progression of the disease by changing the level of cell proliferation,apoptosis and differentiation in acute lung injury.