Lycium barbarum L. also called wolfberry, is a Chinese medicine herb which has been used for thousands of years for the purpose of healthy aging. The content of polysaccharide(LBP) in Lycium barbarum L is more than 40%. While neuroprotective effects of the LBP in neuronal cultures have been demonstrated, it is doubtful whether the LBP can cross through blood-brain barrier to elicit neuroprotection. Therefore, experiments in animal model of senescence-accelerated mouse (SAMP8) were performed to investigate its neuroprotective effects. Early Alzheimer’s disease (AD) is with decreased nicotinic acetylcholinereceptor (nAChR) density from the cortex and hippocampus. α7 nAChRs expressed on cholinergic projection neurons and target regions have been implicated in neuroprotection against β-amyloid (Aβ) toxicity and maintenance of the septohippocampal phenotype. And some studies have determined that oxidative stress is also a decisive factor in AD. For experiments, adult male SAMP8 (5 months with weights 21-24 g) were housed in temperature-controlled animal room subjected to a 12-h light/12-h dark cycle and provided with sufficient food and water supply.The LBP was dissolved in phosphate-buffered saline (PBS). Animals were fed daily with 0.5 ml of either PBS or different dosages of LBP, including 50 and 100mg/kg, for a total of 8 week. We arbitrary chose 1 week for the experiment as Chinese usually drinks the soup containing Lycium barbarum L. for several days.The results suggest that LBP could prevent the appearance of aging sign and symptoms.From Morris Water Maze experiment, we found that taking different dosages of LBP could improve the learning and memory of SAMP8. Under electron and light microscope, we observed that the injuries of the brain was obviously meliorated after taking LBP and the possible mechanism might be related to upregulation of α7nAChRs level and improvement of antioxidant ability.LBP may have potential therapeutic applications to various neurodegenerative disorders.