To explore the effects of surgical operation on helper-inducer T-lymphocytes (Th1/Th2) in sino-nasal neoplasms.From January 2004 to December 2011, 80 patients with malignant tumor in nasal cavities or sinuses were enrolled as experimental group and another 80 subjects with deflection of nasal septum as control group. The phorbol-12-myristate-13-acetate (PMA)-stimulated peripheral blood mononuclear cells (PBMC) were obtained from both malignant tumor and normal control tissues. And flow cytometry was used to detect the expression percentages of interleukin-4 (IL-4) in Th2 cell and interferon-gamma (IFN-γ) in Th1 cell at pre and post-operation.The preoperative expression percentage of CD3(+) CD8(-) IL-4(+) cell in malignant tumor patients was higher than that in controls (6.6% ± 1.7% vs 2.8% ± 1.7%, P < 0.05) while the expression percentage of CD3(+) CD8(-) IFN-γ(+) cell was lower (18.7% ± 5.7% vs 59.3% ± 1.5%, P < 0.05). The preoperative expression percentage of CD3(+) CD8(-) IL-4(+) cell was higher than that at postoperation (6.6% ± 1.7 %vs 2.8% ± 1.5%, P < 0.05). And the postoperative expression percentage of CD3(+) CD8(-) IFN-γ(+) cell was higher than that at preoperation (54.0% ± 4.0% vs 18.7% ± 5.7%, P < 0.05).Surgery may restore the immune balance in patients with malignant tumors in nasal cavities or sinuses.