Immune activities of Opuntia ficus indica L. Miller were investigated through aqueous extracts associated with ultrasonification process at 60℃, and showed the highest promotion of human B and T cell growth, up to 52% and 41%, respectively, compared to the control. The secretion of TNF-α and IL-60 was also enhanced by the addition (0.5mg/ml) of the extracts, up to 48%. NK cell activation was significantly improved up to 1.3 times higher than the case of adding other extracts. It was also found that extracts from O. ficus indica could yield higher nitric oxide production from macrophage than Lipopolysaccaharides (LPS). It can be concluded that, in general, the extracts treated with ultrasonification has higher Immune acitivities than others, possibly by higher yielding immune-modulatory than conventional extraction process. The optimum condition for the extraction of O. ficus-indicais water extraction associated with ultrasonification.