Abstract: The anticancer effect of ethanol-ether extract of Spirobolus bungii Brandt has beenmedically proved with screening experiements. On this basis, the chemical analysis byGC/MS shows that the extract contains a series of ester of fatty acid. Among them oleicacid and methyl oleate are effective anticancer constitutes. It is also proved that theester exists as ethyl ester in the body of Spirobolus bungii Brandt.