Objective To investigate the antitumor effects of phycoerythrin from Gracilaria lemaneiftheormis.Methods The coarse phycoerythrin(CPE) was ig administered to sarcoma180 mice,then the antitumor effect of CPE in vivo was evaluated by the inhibition rate,thymus and spleen indexes.The growth inhibitory effect of phycoerythrin(PE) on cell lines HeLa,EC109,and vascular endothelial in vitro was examined with MTT assay.Influences on HeLa cell cycle and apoptosis of PE were observed by flow cytometry and annexin v-fitc/PI fluorescence staining.Results CPE exhibited inhibitory effect against sarcoma180 growth in mice at the dosage of 100～300 mg?kg-1with a fair dose-effect relationship,and the inhibitory rate was 49.23% at the dosage of 300 mg? kg-1.CPE could also obviously increase the weight of thymus;PE could obviously inhibit the growth of HeLa cell in a dose-effect relationship,the inhibitory rate could reach more than 70%.It could prevent the transforming of HeLa cell cycle from G2/M to S phase to cause apoptosis.But PE couldn't inhibit the growth of EC109 cell,while some growth stimulating effects of PE on vascular endothelial cell were observed.Conclusion The PE from Gracilaria lemaneiftheormis could observably inhibit sarcoma180 growth in vivo.Effects of PE on different cells in vitro were differ,but showed potent inhibitory effect to HeLa cell.