Abstract: Supercritical CO₂ extraction of volatile oil from Momordica charantia L. was studied. The components of volatile oil and its effect on the release of nitric oxide (NO) were analyzed. Response surface methodology (RSM) was used to study the effects of various technological parameters on the yield of volatile oil extracted from Momordica charantia L. by CO₂ fluid under pressure, temperature and time.The components of volatile oil were analyzed by GC-MS. The effect of volatile oil on NO released from RAW 264.7 induced by LPS was evaluated by Gries reagent colorimetry. The results showed that the optimum extraction conditions of volatile oil from Momordica charantia L. were as follows:Extraction pressure 27 MPa, extraction temperature 50℃ and extraction time 90 min. Under these conditions, the yield of volatile oil from Momordica charantia L was 2.56%. GC-MS analysis showed that the main components of volatile oil were phenols, esters, olefins and alkanes, among which phenols were the highest and the relative percentage reached 67.33%. The results of anti-inflammatory analysis showed that the volatile oil could inhibit release NO from RAW264.7 which LPS-induced, and showed a concentration-dependent. To summarize, supercritical CO₂ extraction was an efficient method for extracting volatile oil from Momordica charantia L. The main components of volatile oil of Momordica charantia L. were phenols, which could inhibit LPS-induced NO release from macrophage RAW264.7