The　effects　of　different　concentrations　of　perfluorooctane　sulfonate　(PFOS)　on　the　viability　of　A549　cells　were　determined　by　the　CCK-8　method.　The　effects　of　PFOS　exposure　on　miRNAs　expression　in　A549　cells　were　detected　by　the　next-generation　sequencing　method　to　investigate　the　molecular　mechanism　of　pulmonary　toxicity　caused　by　PFOS.　Target　genes　with　abnormal　expression　of　miRNAs　were　predicted,　and　their　involved　signaling　pathways　and　potential　biological　functions　were　inferred　through　bioinformatics　analysis.　The　results　showed　that　a　low　concentration　of　PFOS　(　©　2021,　Editorial　Board　of　China　Environmental　Science.　All　right　reserved.