[Objective] This article mainly studied the extraction, purification, structure and anti-tumor effects of a novel polysaccharide purified from the fruit bodies of Catathelasma ventricosum (Pk.) Sing. Armillaria ventricosa Peck. [Methods] The polysaccharides of Catathelasma ventricosum (Pk.) Sing. Armillaria ventricosa Peck were extracted with boiling water and purified by DE-52 column and Sephadex G-100 column. The molecular weight, monosaccharide composition and backbone structure were analysed by HPGPC, HPLC, FT-IR, methylation and NMR; the anti-tumor effect was investigated by S-180 tumor-bearing mice and evaluated by the cytokine levels of IL-2, IL-6 and TNF-α in serum samples of the tumor-bearing mice. [Results] A novel polysaccharide was extracted from the fruit bodies of Catathelasma ventricosum (Pk.) Sing. Armillaria ventricosa Peck and named CVP-A, the results had showed that the molecular weight of CVP-A was 10 289, the monosaccharide composition of CVP-A were mainly composed of glucose and a small amount of xylose, with a ratio near 15:2. The results of HPGPC, HPLC, FT-IR, methylation and NMR revealed that CVP-A had a backbone structure of (1→4)-α-D-glucopyranose which branched at the O-2 of the glucose residues. The results of S-180 tumor-bearing mice model had showed that CVP-A had a good inhibiting effect on the experimental S-180 solid tumor, after injection of 25 mg/(kg?d), 50 mg/(kg?d), 75 mg/(kg?d) CVP-A for ten days, the three Kunming mice group had a tumor inhibition ratio of 31.99%, 42.68%, 60.18%, in which the cytokines levels of IL-2, IL-6 and TNF-α in S-180 tumor-bearing mice were increased significantly. [Conclusion] Catathelasma ventricosum (Pk.) Sing. Armillaria ventricosa Peck may be a potential source for anti-tumor development.