We developed a coarse-grained (CG) molecular model, which is useful to investigate a self-assembling process of lipids and surfactants in an aqueous solution or a phase transition process at the molecular resolution. The CG model is designed to reproduce the interfacial properties, solvation free energy, as well as molecular distribution functions obtained from simulations with the all-atomic detail. The systematic CG modeling enabled us to investigate large molecular assemblies such as liposomes with chemical characterization of molecule, which is not accessible by previous phenomenological models. Several application studies given in this paper will elucidate the power of CG molecular dynamics simulation to shed light on molecular processes in lipid membranes happening on the scale of ‹ 100 nm.