An all-atom dimethyl sulfoxide (DMSO) model and a TIP5P water model have been adopted for molecular dynamics simulation. Two new qualities eta(rel)(E) and eta(rel) are introduced to describe the anomalous nonideal behaviors of DMSO-water mixtures. The simulation is compared with chemical shift and excess enthalpy of mixing, which shows good concentration dependences. In addition, our all-atom simulation also indicates that the C-H groups of DMSO may interact with the oxygen atoms of water and DMSO. The weak C-(HO)-O-... contacts and the strong O-(HO)-O-... hydrogen bonds represent the consistent concentration dependences, which exhibits the cooperation effect. (C) 2003 Elsevier B.V. All rights reserved.