The surface modification of micro-fibriled cellulose (MFC) was carried out through the hydrolysis-condensation reaction using (3-aminopropyl)triethoxysilane (APS) and then was subsequently treated with polypropylene-graft-maleic anhydride (MAPP) to give desired MAPP-anchored MFC (MAPP-a-MFC). The confirmation of surface modification for the pristine MFCs was characterized by FTIR, EDX, and XPS measurements. The polypropylene (PP) composites with MAPP-a-MFC were prepared via typical melt-mixing method. The effects of MAPP-a-MFC on the physical properties of the PP composites were investigated. From the results of mechanical properties, thermal behaviors, and the morphology of the composites, it was found that there was an improved interfacial adhesion between the MAPP-a-MFC and PP matrix in the composites.