A　nanorope　is　comprised　of　several　carbon　nanotubes　(CNTs)　with　different　chiralities.　A　molecular　dynamic　model　is　built　to　investigate　the　ionic　adsorption　and　desorption　of　the　CNT　nanoropes.　The　charge　distribution　on　the　nanorope　is　obtained　by　using　a　modified　gradient　method　based　on　classical　electrostatic　theory.　The　electrostatic　interactions　among　charged　carbon　atoms　are　calculated　by　using　the　Coulomb　law.　It　was　found　here　that　the　charged　nanorope　can　adsorb　heavy　metal　ions,　and　the　adsorption　and　desorption　can　be　realized　by　controlling　the　strength　of　applied　electric　field.　The　distance　between　the　ions　and　the　nanorope　as　well　as　the　amount　of　ions　have　an　effect　on　the　adsorption　capacity　of　the　nanorope.　The　desorption　process　takes　less　time　than　that　of　adsorption.　The　study　indicates　that　the　CNT　nanorope　can　be　used　as　a　core　element　of　devices　for　sewage　treatment.