Larimichthys crocea swim bladder is a traditional food and medicine widely used in China. The in vitro anticancer effects of polysaccharide of L. crocea swim bladder (PLCSB) in HCT-116 human colon cancer cells was investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. At concentrations ranging between 0 and 800 μg/ml PLCSB, cancer cell viability was decreased by PLCSB in a concentration-dependent manner. In particular, 400 μg/ml PLCSB significantly (P<0.05) induced apoptosis, which was demonstrated by 4,6-diamidino-2-phenylindole staining and flow cytometry analysis. To elucidate the mechanisms underlying the anticancer effect of PLCSB in HCT-116 cancer cells, the expression of apoptosis and metastasis-associated genes was analyzed by reverse transcription-polymerase chain reaction and western blot analysis. A total of 400 μg/ml PLCSB significantly induced apoptosis in HCT-116 cells (P<0.05) via the upregulation Bax, p53, p21, apoptotic protease activating factor 1, caspase-3, -8, and -9, as well as Fas and the downregulation of B-cell lymphoma 2 (Bcl-2), Bcl-extra large and Fas ligand (L). The results of this study demonstrated that PLCSB exhibits an anticancer effect on HCT-116 colon cancer cells, in vitro.