Abstract: The PBP crude extracts of Sp.-D could be easily obtained. Through repeated freezing and thawing (threetimes) in the presence of 0.001mol/L phosphate buffer used as extractant. the purity (Aλmax/A280) of the PBP crudeextract reached 0.54: The purity could reach about 0.59 by salting-out .but PC and APC was not yet seperated fromeach other f Ailer two-time successive hydroxylapatite (HA) column chromatography. the purities of phycocyanin(PC)and allophycocyanin (APC) could reach 4.1 and 3.5 respectively.

Key words: Spirulina platensis: phycobiliproteins (PBPs) Repeated freezing and thawing Hydroxylapatite(HA)column chromatography