Abstract: Objective:The purpose of this experiment was to purify the water-soluble polysaccharide SSP1-1 from Suaeda salsa and study its antitumor activity. Method:The crude polysaccharide from Suaeda salsa plant was extracted by water extraction and alcohol precipitation. The polysaccharide was further separated and purified by DEAE-52 cellulose column and Sephadex G-75 gel column. The molecular weight(M_W)and purity were analyzed by high performance gel permeation chromatography(HPGPC)and the antitumor activity of SSP1-1 was studied by MTT,hoechst 33342 and western blot. Result:The molecular weight of SSP1-1 was 60.32 kDa,SSP1-1 had a time-dose-dependent inhibition of tumor cell proliferation. When the concentration of SSP1-1 was 500 μg/mL,the cell viability of HepG2 cells was 52.8% and 50.2% at 24 and 48 h,respectively. It was observed that SSP1-1 could cause typical apoptosis characteristics of HepG2 nuclei in Hoechst 33342 staining test. Western blot proved that SSP1-1 could reduce the protein expression of Bcl-2,increase the protein expression of Bax and Caspase-3,and the protein content of each group was significant compared with the control group(P<0.05). Conclusion:SSP1-1 was a homogeneous polysaccharide and had a significant inhibitory effect on HepG2 cells,which laid a foundation for development and utilization of Suaeda salsa polysaccharide.