The cross-type vinylurethane macromonomers (C-VUMs) were successfully synthesized using trimethylolpropane (TMP) as a cross-agent, and applied to the dispersion polymerization of styrene in ethanol. The existence and the structural identification of the reactants and the products were verified using the FT-IR and H-1 NMR spectra. The molecular weight of C-VUM increased, but the polydispersity index of C-VUM decreased with that of PEG. Structural verification of PS spheres synthesized from C-VUMs is carried out using H-1 NMR. However, the molecular weight of polyethylene glycol (PEG) in C-VUM does not affect the particle size of the PS particles, whereas enhanced the uniformity of the PS particles. Thus, C-VUMs act not only as reactive stabilizers, but also as grafting agents (c) 2006 Elsevier Ltd. All rights reserved.