The unicellular red alga,Rhodella reticulata,can synthesize some bioactive substances such as phycobiliprotein and exopolysaccharides.In this paper,isolation and purification of phycocyanin from Rhodella reticulate and its characteristic were studied.The purer phycocyanin was precipitated by(NH4)2SO4 and then purified using DEAE-Sepharose Fast Flow ion exchange column.The purified phycocyanin had an absorbance maximum at 620nm and its purity reached 3.92.Using SDS-PAGE,the molecular mass of intact C-phycocyanin was estimated to be 18 ku and 22 ku with α and β subunits forming dimmers.The phycocyanin of Rhodella reticulate had 17 kinds of amino acid.The antioxidant activity of pure phycocyanin of Rhodella reticulate was higher than that of crude phycocyanin and showed a dose-dependent manner.