To study the chemical constituents and anti-inflammatory activity of the fruit of Citrus medica. The fruit of C. medica was extracted with 95% ethanol, followed by extraction with petroleum ether, ethyl acetate, and n-butanol, successively.GC-MS was used to analyze and identify the chemical composition of the petroleum ether extract, and the chemical composition of the ethyl acetate extract and their inhibition on nitric oxide production was studied.Through GC-MS analysis, there were 57 compounds of the fruit of C. medica with a matching degree greater than 85%, which accounting for 72.50% of the petroleum ether extract.The main components were (E)-5-dodecene (5.61%), 5,7-dimethoxy-2H-1-benzopyran-2-one (5.34%), (Z, Z)-9, 12-octadecanedioic acid (4.72%), etc.Investigation of the EtOAc fraction afforded four compounds, identified as limettin (1), 6, 7-dimethoxycoumarin (2), β-sitosterol (3) and stigmasterol (4).An assay of the inhibition of NO production with RAW 264.7 cells indicated that the petroleum ether extract and the total ethanol extract showed moderate activity with the inhibition rates of (23.40 ± 2.50)% and (7.89 ± 1.28)% at 50 μg/mL, respectively.This article further validates the anti-inflammatory activity of the fruit of C. medica by studying its chemical composition, analyzing its components by GC-MS, and screening for the inhibition of NO production, and provides a basis for the development, utilization, and quality evaluation of this medicinal herb.