This study aimed at determining impacts of various amounts of water-soluble poly-saccharide extracts from brown algae, Padina australis (Hauck) (WPP) on actions of anti-oxidant enzymes, the growth, and non-specific immune response of shrimp, Litopenaeus vannamei (Boone). Triplicate groups of shrimp (1 ± 0.1g) have been given feed 4 iso-nitrogenous and iso-lipidic diets composing of 4 levels; that is, 0 (control), 0.5, 1.0, and 1.5 g kg^-1 of WPP extract for eight weeks. Analyses showed that significantly positive effects of diets with 1.0 g kg^-1 of WPP extract on the growth function of the studied groups. Additionally, improvements of the anti-oxidant enzyme activities, such as catalase, malondialdehyde, super-oxide dismutase, and glutathione peroxidase via feeding 0.5 and 1 g kg^-1 of WPP extracts. Furthermore, activity of phenoloxidase and lysozyme in the treatment fed by 0.5 and 1 g kg^-1 of WPP extract have been considerably greater in comparison to the controls and 1.5 g kg^-1 treatments. Findings demonstrated that usage of 1.0 g kg^-1 of water soluble poly-saccharides extract of the P. australis are useful on growth function, antio-xidant and non0specific immune variables of the L. vannamei.