Abstract: The study was aimed to determine the structure and antibacterial activity of triterpenoids from the vine of Momordica Charantia L..The 75% ethanol ( v / v) was used to extract total triterpenoids from the vine of Momordica Charantia L.. The monomer compound was separated by means of solvent extraction, D101 macroporous adsorption resin column chromatography followed by MCI gel, silica gel and Octadecylsilyl silica gel ( ODS silica gel column chromatography) . The structure was determined by UPLC, ESI- MS, 1D- NMR. The compound was identified as 19- Norlanosta-5, 24- diene-9- carboxaldehyde, 3, 7, 23- trihydroxy-, ( 3β, 7β, 9β, 10α, 23α) -, whose common name was momordicine Ⅰ. Then the broth dilution method was used to test the minimum inhibitory concentrations ( MIC) of triterpenoids.MomordicineⅠhad no significant antibacterial activity against Escherichia coli AB1157.Its MIC were more than 100 μg / m L. MomordicineⅠexhibited the inhibitory effect against Staphylococcus aureus Newman, its MIC were ranged from 12.5 μg / m L to 25 μg / m L.