This paper reports on the influence of maleated polypropylene (MAPP) on the properties of polypropylene (PP)/newspaper flour (PF) composite, and the compatibilization mechanism was also studied. The results of mechanical tests and scanning electron microscope (SEM) showed that MAPP was a true coupling agent for PP/PF blends. The existence of chemical bonds between paper flour and MAPP was proved by gravimetric analysis, while the cocrystallization between bulk PP and PP segments of MAPP was evidenced by differential scanning calorimeter (DSC) and wide angle X-ray diffraction (WAXD) analysis.