Abstract: The present invention relates to composite materials for tire, specifically to composite materials of tire sidewall rubber. A preparation method of the composite materials comprises the following steps of: plasticating rubber in an internal mixer, adding other component except for the sulfur powder and the accelerator to blend, lifting ram piston at 120˜125° C., discharging rubber at 150˜160° C. to obtain rubber compound, then mixing the rubber compound with the sulfur powder and the accelerator in open mill, rolling for 4˜5 times and milling for 5˜8 times to obtain product. The composite materials of the present invention not only meet the requirements of basic mechanical properties of the sidewall rubber, but also obviously improve thermo-oxidative aging resistance and ultraviolet aging resistance of the sidewall rubber, and thereby effectively prolong the service life of the tire.