Herein,　an　easy　and　low　cost　way　is　proposed　to　improve　the　H2O　resistance　ability　of　MnOx　catalyst　for　low-temperature　selective　catalytic　reduction　(SCR),　via　PTFE　modifying.　The　introduction　of　PTFE　to　MnOx　promoted　more　tightly　packed　nanowires,　generating　a　more　hydrophobic　surface.　Mn-PTFE　catalysts　displayed　H2O　and　SO2　resistance,　lowering　the　probability　of　surface　active　sites　being　consumed.　This　work　provides　a　new　insight　into　the　design　of　novel　Mn-based　composite　catalysts　with　H2O　and　SO2　resistance　ability,　as　well　as　promoting　practical　applications　of　Mn-based　catalysts　in　low　temperature　SCR.