Explore the analgesic effects and active components of Lycopodium japonicum Thunb. Ethanol extraction, water extraction and ethanol precipitation were used to obtain different extracts of Lycopodium japonicum Thunb. Using acetic acid writhing and hot plate models, using mouse writhing reaction time and licking rear feet time as indicators, the analgesic components were screened and analyzed by nuclear magnetism. The water extract of Lycopodium japonicum Thunb has analgesic effect. After further analysis and screening, it is found that the analgesic components of Lycopodium japonicum Thunb are polysaccharides. A single component polysaccharide is obtained from the crude polysaccharides, and its structure is analyzed by nuclear magnetic field. The main chain of the polysaccharide is composed of (1→4)-β-glucose, with side chains attached to position 2 and acetyl groups attached to position 6.