Abstract: The chemical constituents of the essential oils from three Cymbopogon plants (C. winteranus, C. citratus and C. distans) were detected by GC-MS. Their antioxidant activity was investigated by the scavenging rate of DPPH free radicals and anti-inflammatory activity were evaluated by inhibition of lipopolysaccharide (LPS)-induced NO production in RAW264.7 cells. The results showed that terpenoids were the main chemical constituents of essential oils from three Cymbopogon plants, with the content of 76.35%~90.52%, of which terpene aldehydes and terpene alcohols were the highest. The main components of C. winteranus, C. citratus and C. distans were (+)-citronellal (37.85%), trans-citral (36.12%) and geraniol (34.76%), respectively. The DPPH radical scavenging activity of the three essential oils was dose-dependent, but lower than that of ascorbic acid (IC₅₀=(0.005±0.002) mg/mL). At a lower concentration (2~4 μg/mL), the ability of three essential oil to reduce NO production was similar to dexamethasone (Dex, 10 μmol/L). The results showed that the three essential oils of Cymbopogon had significant anti-inflammatory activity, C. citratus (IC₅₀ =(0.472±0.121) μg/mL) had the best anti-inflammatory activity, followed by C. winteranus (IC₅₀ = (0.632±0.147) μg/mL) and C. distans (IC₅₀ =(0.669±0.131) μg/mL). Thus they have great development potential as anti-inflammatory drugs and anti-inflammatory products.