Nanofiltration　membrane-based　molecular　separation　has　become　an　indispensable　technology　for　fine　sieving　processes.　However,　the　difficulty　in　regulating　the　separation　performance　restricts　the　applicability　of　these　nanofiltration　membranes　in　different　separation　systems.　Herein,　we　will　show　that　the　separation　performance　of　Ti3C2Tx-MXene　lamellar　nanofiltration　membranes　on　certain　dye　molecules　can　be　modulated　by　employing　external　electrostatic　fields.　Specifically,　for　cationic　dyes,　the　negative　voltage　applied　to　Ti3C2Tx　lamellar　nanofiltration　membranes　can　improve　their　sieving　abilities　on　dyes　but　reduce　their　water　flux　at　the　same　time.　On　the　contrary,　a　positive　electric　field　will　cause　a　decline　in　the　retention　capacities　but　improve　the　water　flux　of　the　membranes.　Interestingly,　when　using　anionic　dye　molecules　as　solute　models,　the　filtration　performance　of　the　Ti3C2Tx　membranes　exhibits　completely　opposite　variations　to　that　of　filtering　cationic　dyes,　whether　the　applied　electric　field　is　negative　or　positive.　The　regulation　mechanisms　for　the　filtration　performance　of　Ti3C2Tx　membranes　have　been　discussed,　which　are　probably　ascribed　to　the　changes　in　the　electrostatic　interactions　between　dyes　and　Ti3C2Tx　induced　by　the　external　electric　field.　Our　findings　indicate　that　the　filtration　performance　of　MXene　lamellar　membranes　on　both　cationic　and　anionic　dyes　can　be　modulated　by　applying　an　external　electric　field,　opening　up　enormous　opportunities　to　use　such　electrified　nanofiltration　membranes　in　the　field　of　membrane-based　molecular　separations.