Molecular dynamics simulations of B-DNA in aqueous solution containing Na+ and K+ ions, or Na+, K+ and one kind of Sr-90(2+), Cs-137(+) or I-131(-) are investigated at 298 K. For the ions in the minor groove, K+ ions are dispersed as Sr2+ or Cs+ added, but Na+ ions dominate the minor groove when I- ions are added. For the ions in the major groove, the interaction of K+ and DNA becomes stronger as I- added. As for the DNA conformation, Cs+ ions affect most while Sr2+ ions the least. (C) 2013 Elsevier B.V. All rights reserved.