A simple method to improve the hydrophobicity of microcrystalline cellulose (MCC) through modifica- tion by using soybean oil was developed. The method consists of mixing soybean oil ethanol solution with pretreated MCC and heating at 110◦C. Fourier transform infrared spectroscopy, X-ray diffraction and wettability test were used to characterize the modification of MCC. The results showed that the pretreatment of ultrafine pulverization significantly enhanced the modification of MCC. The crystalline structure of MCC was not destroyed during the pretreatment and the modification. The modified MCC displayed a higher affinity for low polar solvents such as dichloromethane and toluene.