The molecular dynamics simulation of the spontaneous formation of zwitterionic micelle of 3-(N,N-dimethyldodecylammonio)-2-hydroxy-propanesulfonate (abbreviated as DSB) in sodium chloride (NaCl) solution has been performed based on a coarse grained model. By evaluating the properties of DSB micellar structure, we can obtain the results that the polar groups in the DSB monomers are unfolding on the surface of the micelle forming a dipolar layer, some ions of NaCl have been restricted inside the dipolar layer and the concentration of NaCl ions in the dipolar region is greater than that in the bulk. (c) 2007 Elsevier B.V. All rights reserved.