Abstract： Objective To investigate the effect of vascular endothelial growth factor (VEGF) on the differentiation, formation and function of the dendritic cell (DC) in peripheral blood of patients with oral squamous cell carcinoma (OSCC).Methods Flow cytometry was used to detect the number of DC in peripheral blood of 81 patients with OSCC, and ELISA applied to test serum VEGF concentration the OSCC patients, and immunohistochemistry used to observe the expression of VEGF in primary foei of 57 patients with OSCC.DC from CD-14 peripheral blood mononuclear cells were cultured with VEGF165 in vitro to investigate the cytokine's effect on DC.Results In comparison with controls[(325.70±117.54) ng/L], the level of serum VEGF [(764.33±263.64) ng/L] was significantly increased (P < 0.01) and the DC numbers was significantly decreased (P < 0.01) in patients with OSCC.There was a negative correlation between serum VEGF concentration and the level of DC (P < 0.01).The expression of VEGF in primary focus was positively correlated with serum VEGF concentration, but was negatively correlated with the level of peripheral blood DC (P <0.01).DC cultured in vitro with VEGF165 decreased the expression of CD-1a, CD-40,CD-80, CD-86, CD-83, HLA-DR, and revealed a lower ability of stimulating T lymphocyte proliferation but a higher ability of uptake, compared to controls.Conclusions The overexpressed VEGF in patients with OSCC might be one of the important reasons for blocking the differentiation and maturation of DC.