Abstract: Objective: To explore the effect of polysaccharides from Chlorella (PFC) on the maturation of hu-man dendritic cells (DC) and its related mechanism.Methods: The immature DC derived from peripheral blood mononuclear cells was interfered with with purified PFCS.Flow cytometry was used to detect the expression changes of CD83 and CD86 on the DC surface after the intervention of PFCS, and the cytokine levels of IL-6, TNF-α and IL-10 were detected by enzyme-linked immunosorbent assay(ELISA).Then, the transcriptional gene expression difference and pathway enrichment analysis between the PFC treatment group and the control group were compared to find the action pathway, and the related molecular pathway inhibitors were used for prelimi-nary verification.Results: PFC could up-regurate the expressions of CD83 and CD86 on the surface of DC and promote the release of IL-10.The results of bioinformatics analysis showed that PFC might play a role through Toll-like receptor 2/4 (TLR2/4).TLR2 and TLR4 pathway inhibitors were used to down-regulate the PFC-in-duced expression of CD86 in DC.The expression level of CD86 significantly decreased after TLR4 inhibitor in-tervention (P< 0.05).Conclusion: PFCS may up-regulate the expression levels of DC surface markers: CD83 and CD86 derived from human peripheral blood mononuclear cells through TLR2 and TLR4 pathways, thus pro-moting DC maturation.