Purpose To study the polysaccharide from Pinus massoniana pollen(PPM)and to compare its anti-tumor,immune modulation activities and scavenging qualities of free radical with its sulfated derivative(S-PPM).Methods PPM Wag chemically modified by chlorosulfonic acid-pyfidine method and their bioactivities were compared.Results The substituting degree of S-PPM was 1.47.Results showed that S-PPM was more powerful in inhibiting the growth of tumor cell in vivo and in vitro and in promoting T,B lymphocytes than PPM.But there Wag no remarkable difference in promoting phagocytosis of macmphages.S-PPM was stronger in scavenging superoxide anion radical than PPM but it wag vice versa in scavenging hydroxyl radical.Conclusion S-PPM inhibited the cancer cell growth mainly through specific immunity.Sulfate of PPM influenced its quality of scavenging free radicals greatly.