Abstract: Octenyl succinic hydroxyethyl cellulose ester was prepared by wet process.Fourier transform infrared spectroscopy (FTIR) , UV-Vis spectra and scanning electron microscope (SEM) were employed to analyze the characters and structure of octenyl succinic hydroxyethyl cellulose ester, such as apparent viscosity, transparency, freeze-thaw stability, emulsibility and emulsifying.The infrared data showed that HEC reacted with octenyl succinic anhydride, bringing only octenyl succinic anhydride groups but not any other groups.And other results indicated that the apparent viscosity of prepared HEC increased by 60% and not affected by pH.Moreover, the emulsibility increased and the emulsion stability with increasing degree of substitution gradually tended to 1.The embedding of oil encapsulated with prepared HEC was fine.The embedding efficiency was higher (93.39%) .It could be concluded that the properties of prepared HEC was good, and it could be used as emulsifier material of microcapsule.