Cirsilineol (4′,5-dihydroxy-3′,6,7-trimethoxyflavone) is a compound isolated from the herb of Artemisia vestita Wall (Compositae). In this study, we aimed at examining the anti-proliferative activity of cirsilineol against multiple types of cancer cells and the underlying mechanisms. Cirsilineol significantly inhibited proliferation of Caov-3, Skov-3, PC3 and Hela cells in a concentration-dependent manner. The compound also dose-dependently induced apoptosis in Caov-3 cells, as determined by annexin V/propidium iodide staining. Besides, cirsilineol induced a remarkable change in mitochondrial membrane potential and caused release of cytochrome c to cytosol. Furthermore, the compound caused a marked activation of capase-3, caspase-9 and poly (ADP-ribose) polymerase (PARP). These results suggested that the induction of apoptosis via the mitochondrial pathway was involved in the anti-proliferative activity of cirsilineol against cancer cells.