Ramie fiber and high density polyethylene (HDPE) were used as raw materials, ramie fiber/HDPE composites were prepared by compression molding process, tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)] methane(1010A) was used as anti-oxidant, the thermo-oxidative aging test was carried out and the variations in properties of different composites during aging were studied. The results show that, the composite containing 3%1010A has the greatest flexural strength at each aging stage, and the composite using anti-oxidant has greater impact strength and peak melting temperature than the composite without 1010A during aging test, when aging happens, the former also has greater melting index at each aging stage. The composite with anti-oxidant is more color stable during the aging test. All the results indicate that 1010A enhances the composite aging resistance.