Peanut (Arachis hypogaea L.) holds a pivotal role as a vital oil crop globally. However, its yield and quality often suffer severely due to salt stress. Although nanomaterials have significant potential for enhancing the salt tolerance of crops, research regarding in peanuts remains relatively scarce. Furthermore, our comprehension of the mechanisms and crucial responsive genes involved in nano-enhanced crop salt tolerance is still limited. In this study, we found that foliar application of polyacrylic acid-coated nanoceria (PNC, at 0.6 mM for 5 d) markedly increased the biomass of peanut seedlings under NaCl treatment (at 300 mM for 5 d). Further research found that the PNC application triggered the several processes, including reduced production of reactive oxygen species (ROS), improved antioxidant capacity, and increased K