Al(OH)(3)/polypropylene (PP) composites modified by polypropylene grafted with acrylic acid (FPP) were prepared by melt extrusion. Effect of PP grafting with acrylic acid on mechanical properties and fracture morphology of Al(OH)(3)/polypropylene composites were investigated. Although incorporation of Al(OH)(3) reduced the mechanical properties of PP, addition of FPP increased the mechanical properties of Al(OH)(3)IPP composites. It is suggested that addition of FPP improve the dispersion of Al(OH)(3) and the interfacial interaction between filler and matrix. Mechanical properties of Al(OH)(3)/FPP/PP composites depend on the grafting rate and the content of FPP.