PP and recycled corrugated paper board as the raw material and MAH-g-PP, aluminum ester and aluminum-titanium compound coupling agent were used to investigate the mechanical performance of fiber reinforced PP composites. The results show that: the tensile strength increases while the impact strength decreases with the loading of fiber without solubilizer; both the bending and tensile strength reaches the highest point when the MAH-g-PP loading stays at 30wt%; among the three mentioned coupling agents, MAH-g-PP is superior to modify the interface; the impact strength, tensile strength and bending strength obtain an optimized value when the MAH-g-PP content is 10% to fiber filled.