The polarity of MCC could be modified by mixing with soy- bean oil and heating at 110 ◦ C. The pretreatment of ultra-fine pulverization significantly improved the modification extent of MCC. After the modification, MCC displayed a higher affinity for low polar solvents, and the hydrophobicity of the modified MCC could be adjusted by controlling the heating time. Since the pre- treatment and the modification did not disrupt the crystalline structure of MCC, the developed method provides a route for preparing MCC reinforced composites with hydrophobic polymer matrices.