Leaves of Adinandra nitida constitute a kind of flavonoid-rich plant food. In this study, camellianin A, the main flavonoid in the leaves of Adinandra nitida,was prepared and identified by high performance liquid chromatography-photodiode array detector-electrospray ionization mass spectrometry (HPLC-PDA-ESI/MS). In the anticancer assay, it was found camellianin A could inhibit the proliferation of the human hepatocellular liver carcinoma Hep G2 and human breast adenocarcinoma MCF-7 cell lines in a dose-dependent manner and induce the significant increase of the G0/G1 cell population. After treated by camellianin A, phosphatidylserine of Hep G2 and MCF-7 cells could translocate significantly to the surface of the membrane. The increase of an early apoptotic population of Hep G2 and MCF-7 cells was observed. It was concluded that camellianin A not only affected the progress of the cell cycle, but also induced cells to enter into apoptosis.