We report the molecular dynamics simulations of the adsorption of DNA bases on (8, 8) carbon nanotubes (CNTs) in solvent environment. The adsorption processes of bases on neutral and charged CNTs have been observed. Results show that bases can rapidly adsorb on the sidewall of neutral CNTs due to the van der Walls interaction. But the binding geometries of the bases-CNT change with the charge density of CNT, bases no longer stack on highly charged nanotube surfaces. The competition between polarized water and bases results in the instability of the adsorption of DNA based on charged CNTs. (C) 2011 Elsevier B. V. All rights reserved.