OBJECTIVE To investigate the effects and mechanism of Glycyrrhiza inflata polysaccharides （GiP） and GiP-B1 on the maturation and anti-tumor effect of dendritic cell （DC）. METHODS The immature DC （imDC） of hepatocellular carcinoma cell H22 tumor-bearing mice cultured in vitro were divided into control group， tumor necrosis factor-α （TNF-α） group， GiP group， and GiP-B1 group. The viability， positive expressions of surface markers （CD11c， CD80， CD86， MHC-Ⅱ）， the levels of interleukin-12p70 （IL-12p70） and IL-4 in mature DC （mDC） of tumor-bearing mice were detected. mDC and CD4+T lymphocytes were co-cultured to generate CD4-cytotoxic T cell （CD4-CTL）； stimulation index， the levels of IL-12p70， interferon-γ （IFN-γ）， IL-4 and IL-10， the killing activity of CD4-CTL to H22 cell were detected. mRNA expressions of IL-12， IL-12 receptor （IL-12R）， signal transducer and activator of transcription-4 （STAT-4）， as well as the protein expression of IL-12 receptor β2 （IL-12Rβ2）， phosphorylation levels of nuclear factor-kappa B （NF- κB） p65 and STAT-4 proteins in mDC were detected after co-culture. RESULTS Compared with the control group， the viability of mDC， the positive expressions of MHC-Ⅱ， and the levels of IL-12p70 and IL-4 were increased significantly in GiP group and GiP-B1 group （P＜0.05）. The positive expressions of CD11c， CD80 and CD86 showed an increasing trend， but the differences were not statistically significant （P＞0.05）. After co-culturing， the stimulation index， the levels of IL-12p70 and IFN-γ were significantly increased （P＜0.05）， while the levels of IL-4 and IL-10 （except for the GiP group） were significantly decreased （P＜0.05）； the cytotoxicity against H22 cells was significantly enhanced （P＜0.05）. mRNA expressions of IL-12 and IL-12R （except for GiP group） and STAT-4， protein expression of IL-12Rβ2 as well as phosphorylation levels of NF-κB p65 and STAT-4 protein were increased significantly in mDC （P＜0.05）. CONCLUSIONS GiP and GiP-B1 have a good promoting effect on the maturation of DC in tumor-bearing mice， effectively stimulate CD4+T cell proliferation， enhance the anti-tumor activity of CD4-CTL，and its mechanism may be related to activating IL-12/NF-κB/ STAT-4 signaling pathway.