Water molecule transportation through a single-walled carbon nanotube under a charge influence on tube was simulated.As the charge located at middle tube increases from 0.0e to 0.7e,water molecular orientations develop from a consistent orientation(0≤q≤0.4e) to bipolar orientations(L defect,when q≥0.5e).Water molecule permeation through the channel is almost the same as in charge-free nanotube when q≤0.2e.As q increases further the permeation decreases sharply.When q=0.6e the permeation becomes negligible and the tube channel effectively closes. Water molecule transportation through a single-walled carbon nanotube under a charge influence on tube was simulated. As the charge located at middle tube increases from 0.0e to 0.7e, water molecular orientations develop from a consistent orientation (0 ≦ q ≦ 0.4e) to bipolar orientations (L defect, when q≥0.5e) .Water molecule permeation through the channel is almost the same as in charge-free nanotube when q≤0.2e.As q increases further the permeance decreases sharply. Whilst q = 0.6e the permeation becomes negligible and the tube channel effectively closes.