Abstract: The water soluble polysaccharides of peach were extracted in water, and then isolated by ethanol, through DEAE-sehparose cation exchange column chromatography and Sephacryl G-300 gel column chromatography, we got two polysaccha-rides HTP1 and HTP2. In this paper, we studied the Effect of Scavenging Free-radical of HTP1 and HTP2. The results showedthat they had a evident effect in scavenging •OH, Their IC50 were 270.92μg/ml and 4.361mg/ml. HTP1 had a evident effectin scavenging O2-, the IC50 was 401.3μg/ml, but HTP2 had no effect on O2-. HTP1 and HTP2 had relatively high growth-inhibition activities against Lewis lung carcinoma and enhanced immune function of the mice, whice took it. HTP1 and HTP2were injected by C5BL/6 mice at two dosages of 100 mg/kg per day and 200 mg/kg per day, the inhibition rate of Lewis lungcarcinoma by subcutaneous inoculation to mice at toe were about 43.44%～54.69% and 44.48%～47.08% respectively.Meanwhile, HTP1 and HTP2 enhanced the activities of NK cells and lymphocyte activities of tumor-bearing mice.

Key words: A.Persica.L.var.seleropersica, polysaccharides, antitumor activity, scavenging free-radical Enhance immune