Febrile seizures (FS) is the most common type of seizures in children. Evidence indicating cognitive effects that FS exert that persist into adulthood is inconsistent. To investigate the mechanisms underlying long-term cognitive effects induced by FS, we examined specific measures in adult rats previously subjected to experimental FS. Rats were separated into hyperthermia-seizure (HS) group which experienced serious seizures, and hyperthermia-non-seizure (HN) group which did not experience seizures after each hyperthermia inductions. Based on Morris water maze and novel object recognition tests, we found that adult rats exhibited better spatial and non-spatial learning and memory performance in HS group. To further illustrate the mechanism of this phenomenon, we found greater long-term potentiation (LTP) in hippocampal area CA3, higher expression of synaptic plasticity-related factors (CREB, p-CREB and synapsin), and raised synaptic curvatures in HS group compare with HN group. Therefore, we conclude that low-intensity seizures may promote hippocampus-associated learning and memory functions by enhancing synaptic plasticity. Our findings may be useful for understanding the pathogenesis of long-term changes in cognitive function induced by FS.