The aim of this paper was to study the antitumor and immunoregulatory activities of a polysaccharide (TTP) from Talinum triangulare. The molecular weight of TTP-IV was 49.9 kDa. The monosaccharide composition analysis of TTP-IV revealed that it was a heteropolysaccharide consisting of rhamnose, arabinose, mannose and galactose with a molar ratio of 1.22 : 1.00 : 1.05 : 1.51. The results of the in vivo study showed that TTP (200 mg per kg bw) significantly inhibited the growth of tumor by 49.07% in H22-bearing Kunming mice. In vitro, the growth of primary murine macrophages was promoted by TTP in a dose- and time-dependent manner significantly. Besides, RAW 264.7 cells were activated by TTP to produce NO and the toxicity of RAW 264.7 supernatant was markedly enhanced in vitro. The levels of iNOS, TLR2, TLR4 and IL-1β were obviously increased by TTP. Therefore, it is suggested that TTP can be utilized as a potent antitumor and immunoenhancing material in functional food.