[Abstract] Objective: To detect the expression of miR-126 in oral squamous cell carcinoma (OSCC) and to analyze its correlation with clinicopathological features and prognosis of patients, as well as to explore the effect of miR-126 over-expression on the malignant biological behaviors of Tca8113 cells. Methods: A total of 62 pairs of cancer and para-cancerous tissue specimens from OSCC patients who were surgically treated in the First Affiliated Hospital of Zhengzhou University from June 2016 to June 2018 were collected for this study; in addition, human tongue squamous carcinoma Tca8113 cell line and human mouth keratinocyte HOK cell line were also selected for this study. The expression of miR-126 in cancer tissues and cells was detected by qPCR, and the relationship between miR-126 expression and clinicopathological features and prognosis of the patients was analyzed. miR-126 mimics and miR-NC plasmids were respectively transfected into Tca8113 cells by liposome transfection technology. Cell proliferation, apoptosis, migration and invasion were detected by MTT method, Flow cytometry and Transwell chamber method, respectively; and the expressions of apoptosis, migration and invasion related proteins were detected by Western blotting. Results: The expression level of miR-126 in OSCC tissues and Tca8113 cells was significantly lower than that in para-cancerous tissues and HOK cells (all P<0.01). The expression of miR-126 was associated with TNM stage and lymph node metastasis (all P<0.05), and patients with high miR-126 expression had significantly better overall survival rate than patients with low expression (P<0.05). After transfection with miR-126 mimics, the cell proliferation, migration and invasion ability significantly decreased (P<0.05 or P<0.01) while the apoptosis rate significantly increased in Tca8113 cells (P<0.01), the expression levels of Bcl-2, N-cadherin and vimentin in Tca8113 cells significantly decreased (all P<0.01), and expression levels of Bax and E-cadherin significantly increased (all P<0.01). Conclusion: miR-126 is low expressed in OSCC tissues and Tca8113 cells. Up-regulation of miR-126 inhibits cell proliferation, migration and invasion and promotes apoptosis of Tca8113 cells.