Background and purpose: It was reported that activins, members of transforming growth factor-β superfamily, could induce several tumor cells into apoptosis. This study was designed to observe the effects of recombination human activin A on proliferation and apoptosis ofA549 cells. Methods: A549 cells were cultivated by routine method, then treated with different concentrations of recombination human activin A. Inhibitory effect of activin A on A549 cell proliferation was detected by MTT assay, and apoptosis of A549 cells was determined by flow cytometry. The expression of type Ⅱ receptors of activin (ActR Ⅱ and ActR Ⅱ B) was detected by Western blot. Results: Recombination human activin A inhibited the proliferation ofA549 cells in time-dependent and dose-dependent manners. Increases of apoptosis in A549 cells and expression of ActR I] and ActR ⅡB occurred dose-dependently after treated with acfivin A. Conclusion: Recombination human activin A inhibited cell proliferation and induced apoptosis in A549 cells, at least in part, by inducing expression of type Ⅱ receptors of activin and activation of its downstream signaling.