Seed aging tolerance during storage is generally an important trait for crop production, yet the role of small auxin-up RNA genes in conferring seed aging tolerance is largely unknown in rice.  In this study, one small auxin-up RNA gene, OsSAUR33, was found to be involved in the regulation of seed aging tolerance in rice.  The expression of OsSAUR33 was significantly induced in aged seeds compared with unaged seeds during the seed germination phase.  Accordingly, the disruption of OsSAUR33 significantly reduced seed vigor compared to the wild type (WT) in response to natural storage or artificial aging treatments.  The rice OsSAUR33 gene promotes the vigor of aged seeds by enhancing their reactive oxygen species (ROS) level during seed germination, and the accumulation of ROS was significantly delayed in the aged seeds of Ossaur33 mutants in comparison with WT during seed germination.  Hydrogen peroxide (H₂O₂) treatments promoted the vigor of aged seeds in various rice varieties.  Our results provide timely theoretical and technical insights for the trait improvement of seed aging tolerance in rice.