Objective: To investigate the expression of BRD4 in squamous cell carcinoma (SCC) tissues and cells, and the effects of its expression on cell proliferation and invasion ability. Methods: Immunohistochemistry was used to detect BRD4 protein expression in SCC tissues and paired normal esophageal squamous epithelial tissues. The expression of BRD4 protein was detected in different SCC cell lines and normal esophageal squamous epithelial cells by Western blot. BRD4 siRNA and control siRNA were used to transfect SCC Eca109 cells, and experiments were divided into three groups: untreated group, control siRNA group and BRD4 siRNA group. Western blot was employed to investigate the expression of BRD4 protein in the three groups of SCC Eca109 cells. CCK-8 kit was utilized to detect cell proliferation ability, and Transwell chamber was used to examine cell invasion ability. Finally, Western blot was used to detect the expression of MMP2 and MMP9 proteins. Results: The positive rate of BRD4 protein expression in SCC tissues was significantly higher than that of normal squamous epithelial tissues. The expression of BRD4 protein in 4 SCC cell lines was higher than that in normal esophageal cell Het-1A. BRD4 siRNA obviously downregulated the expression of BRD4 protein in Eca109 cells, and its downregulation contributed to the suppression of cell proliferation and invasion ability in Eca109 cells (all P<0.05), coupled with the decreases of MMP2 and MMP9 proteins. Conclusion BRD4 may be closely associated with the proliferation and invasion of SCC, and it thus may be a potential therapeutic target for SCC.