Abstract: In order to investigate the effect of rice husk fiber pretreatment method (hydrothermal, microwave, alkali treatment and benzoylation treatment) on the thermal and anti-aging behavior of rice husk fiber/polyvinyl chloride (PVC) composites in simulated soil aging conditions, the TG curves of rice husk fiber/PVC composites were performed by a comprehensive thermal analyzer. The linear thermal expansion coefficient, mechanical and water absorption properties of rice husk fiber/PVC composites were characterized and the microstructure was observed by SEM. The results indicate that all the four treatment methods can improve the thermal behavior and anti-aging properties of rice husk fiber/PVC composites. The surface of the treated rice husk fiber is rougher, and the better interface of fiber and matrix lead to reducing micro-cracks. After 21 days simulated soil aging, the thermal initial decomposition temperature of benzoylated rice husk/PVC composites increases by 3.9%, compared with the untreated rice husk fiber/PVC composites. The linear thermal expansion coefficient and 24 h water absorption of benzoylated rice husk fiber/PVC composites decrease by 6.72% and 55.6%, respectively. The tensile strength and hardness increase by 103% and 119%, respectively. The benzoylated rice husk fiber/PVC composites have a good interface, and the rice husk fiber distribute uniformly. So the sequence of the four pretreatment methods is:benzoylation treatment > alkali treatment > hydrothermal treatment > microwave treatment.