Abstract: To explore the protective effect of Lycium barbarum polysaccharide(LBP)on lipopolysaccharide(LPS)-induced BV2 microglia. In this study,MTT assay was used to detect cell viability,ELISA was used to detect the secretion of inflammatory factors,and Western Blot was used to detect protein expression. The results showed that the activity of BV2 microglia treated with LPS alone had no significant change,but the release of inflammatory factors PGE2,IL-1 β,IL-6 and TNF-α in the supernatant of BV2 microglia cells increased significantly. After LBP gradient was co-incubated with LPS-induced BV2 microglia for 24 h,the activity of LPS-induced BV2 microglia was effectively enhanced and the release of LPS-activated BV2 microglia inflammatory factors was significantly inhibited(P<0.05). The results of flow cytometry showed that microglia in LPS group could produce a large amount of ROS,and the content of ROS in microglia was significantly decreased after being treated with different concentrations of LBP for 12 h. The results of Western Blot showed that the protein expression of NF-κB signaling pathway and nucleusp 65 protein were significantly up-regulated in LPS group and LBP group,and were inversely proportional to LBP concentration,while p65 protein expression in cytoplasm of control group was significantly higher than that in LPS group and LBP group,and decreased with the increase of LBP concentration. This study showed that LBP had a significant protective effect on LPS activated BV2 microglia,inhibited the inflammatory response induced by LPS activated BV2 microglia,and inhibited the content of ROS in microglia to play an anti-oxidation stress effect,and effectively inhibited the expression of p-TAK1,iκB,p-iκB and p-p65 after LPS stimulation.