Abstract: Objective To investigate the expression of IL-17 and Foxp3 in peripheral blood and tumors tissues in patients with oral squamous cell carcinoma(OSCC) and their clinical significance. Methods The cancer tissues from 40 patients with primary OSCC confirmed pathologically were selected. They were compared with the normal mucosal epithelial tissues of 20 patients with benign oral tumor. We collected peripheral blood specimens of experimental group and control group before operation. The proportion of IL-17 and Foxp3 in peripheral blood, and the expression of CD3, CD4, CD8 and CD56 were detected by flow cytometry. The expression of IL-17 and Foxp3 were determined by SP method of immunohistochemistry in the tissues from surgical specimens of experimental group and control group. The objects were divided into Group A(stage Ⅰ, Ⅱ), Group B(stage Ⅲ, Ⅳ)and Group C(normal). Results Compared with Group C, peripheral blood from patients in Group A and B showed higher quantification of CD4+IL-17+ cells and CD4+Foxp3+ cells concentration. IL-17 quantification in peripheral blood from patients with OSCC showed positive correlation with Foxp3 concentration (r=0.772, P<0.05). Compared with Group C, there were obvious differences in declining percentage of CD3+ and CD4+ cells, declining ratio of CD4+/CD8+, and increasing percentage of CD8+ cells in Group A and B(P<0.05). The positive expression rates of IL-17 and Foxp3 in the tissues from Group B were obviously higher than those from Group A; moreover, those from Group A and B were obviously higher than those from Group C(P<0.05). IL-17 quantification in OSCC tissues showed positive correlation with Foxp3 concentration in Group A and B(r=0.386, P<0.05). Conclusion IL-17 and Foxp3 may promote the development and progression of OSCC, and this effect probably is associated with body immune status.