Abstract: Terpene-based epoxy resin polyol (T-N) was prepared via the reaction of terpene-based epoxy resin(TME) and neopentyl glycol(NPG). Then the T-N was modified with hydroxypropyl terminated polysiloxane(HTP), 2,4 tolylene diisocyanate(TDI) and 2,2-bis (hydroxymethyl) propionic acid(DMPA) to obtain the anionic polysiloxane-modified terpene-based epoxy resin polyol (T-N-S) dispersion. The chemical structure of the T-N-S was characterized by FT-IR and NMR. The micro-morphology of T-N-S was determined by transmission electron microscopy (TEM) and particles size measurement. And the effects of reaction condition and siloxane content on the stability and micro-structure of the polyol dispersion were studied. T-N-S dispersion was obtained at the conditions of DMPA and TDI were mixed with the molar ratio 1:2 in the presence of solvent acetone (the amount of solvent was 1.5-2 times based on the reactants mass) and refluxed at 56℃ for 3 h. Then HTP and T-N were added in to the reaction and continued to feflux for 4 h. The obtained T-N-S dispersion showed good stability and the particle size of the dispersion ranged from 100 to 300 nm when the dosage of HTP was 3%-12% of T-N by weight.