Abstract: The polypropylene is filled and modified with rutile nano-titanium dioxide as anti-aging additives. The property and feature of rutile nano-titanium dioxide are gained by a series of indicating methods, such as TEM, XRD, UV-VIS and so on. Polypropylene is degradated by accelerated aging test with xenon arc lamp. The variation law for mechanical properties of polypropylene is studied during the weathering test in contrast. The fracture morphology of polypropylene and the disperse state of rutile nano-titanium dioxide are analyzed by SEM. It is noted that rutile nano-titanium dioxide and its composites can upgrade the toughness and strength of polypropylene, improve the weatherproof property of polypropylene, and prolong the service life of polypropylene.