The fruits of Avicennia marina are widely used for both medicine and food in Guangxi of China. As a part of ourcontinuous effort to search for bioactive molecules from the plant, the fruits of A. marina were investigated, which has ledto one new triterpenoid saponin (1) and 29 known compounds been isolated and their structures were established by usingspectroscopic methods and comparing with literature data. The new triterpenoid saponin showed cytotoxicity against GSC-3# and GSC-18# with the IC 50 values were 12.21 and 5.53 lg/mL respectively, and most of the known compounds hadsignificant antioxidant capacity with the IC 50 values ranging from 0.36 to 13.07 lg/mL.