Natural plant extract has been the subject of intense research aiming in elucidating the underlying mechanisms of their chemopreventive effects upon various forms of human cancers. The objective of our study was to evaluate the natural antioxidants and anticancer agent potential of Phyllostachys. The chemical composition of steam extract from Phyllostachys was carried out using GC-MS. The steam extract of Phyllostachys was dominated by monoterpenes (62.96% - 71.36%) and sesquiterpenes (23.58% - 33.13%) as the main compounds. The antioxidant activities of the steam extract was determined using a DPPH scavenging and hydrogen peroxide scavenging activity test systems. Furthermore, the amounts of total phenolics in steam extract were determined spectrometrically The steam extract of P. pubescens and P. bambusoides were presented the high activity (69.4% and 64.0%, respectively.). The steam extract from Pyllostachys species showed a hydrogen peroxide scavenging activity of approximately 50.4% - 54.6% when compared to that of the standard gallic acid. The anticancer activities of steam extract were determined using a MTT assay. Assessment of the cytotoxic effect of the steam extract on PC-3 cells showed that the P. bambusoides (20.85%) and P. pubescens (20.41%) were superior in induced cytotoxicity compared with the steam extract of P. nigra var. henonis (1.15%). Findings from this study indicated that steam extract of P. bambusoides and P. pubescens possessed potential as medicinal drug especially in prostate cancer treatment.