C-phycocyanin and polysaccharide were isolated and purified from spirulina. By using the techniques of colony forming unit-erythroid (CFU-E) culture of fetal liver cells in mice in vitro, C-phycocyanin was found to possess high erythropoietin (EPO) activity. The effects of polysaccharide and phycocyanin on the periphyeral blood and bone marrow hematopoietic stem and progentitor cell in normal, irradiated and anemic mice were studied. These studies demonstrate the unique capacity of C-phycocyanin and polysaccharide to influence the differentation and proliferation of committed hematopoietic progenitor cell. Stimulated recovery by C-phycocyanin and polysaccharide was observed in leukocyte and bone marrow nucleated cell counts and the number of CFU-GM colony formation in mice after single whole-body gamma-ray irradiation. The C-phycocyanin and polysaccharide can lower the anemic degree of mice combined with treatment of gamma-ray irradiation and benzohydrazine hydrochloric acid peritonerl injection.