A simple model, i.e., sodium bis(2-ethylhexyl) sulfosuccinate (AOT) represented by one-head and two-tail beads tied together by a harmonic spring and water or iso-octane by one bead, was put forward via dissipative particles dynamics (DPD) simulation method. Using the changes of interfacial tension between water and oil phase, a ternary phase diagram of AOT/water/iso-octane system was drawn. (C) 2002 Elsevier Science B.V. All rights reserved.