Objective To observe the effect of GA on the proliferation and apoptosis of SCC-9 cells and explore its possible mechanism.Methods The SCC-9 cells were divided into control group, and low, medium and high concentration gallic acid groups (30, 60, 90 μM GA). Cell proliferation was detected by MTT assay. The cell cycle and apoptosis rate of SCC-9 were detected by flow cytometry. The apoptosis of SCC-9 cells in each group was detected by TUNEL method. The expressions of Cl-caspase9, Cl-caspase8, Cl-caspase3, Cl-PARP, p-ERK1/2, p-JNK1/2 and p-p38 in SCC-9 cells were detected by Western blotting. Results Compared with the control group, the proliferation rate of SCC-9 cells in low, medium and high concentration gallic acid group decreased gradually, while the DNA content in sub G1 phase, apoptosis rate and the number of positive apoptotic cells increased gradually in a dose-dependent manner. Compared with 〖JP2〗the control group, the protein expression of Cl-caspase9, Cl-caspase8, Cl-caspase3, Cl-PARP, p-ERK1/2, p-JNK1/2 and p-P38 in the gallic acid group was gradually increased in a dose- dependent manner (P<0.05).Conclusion GA can inhibit the proliferation and induce apoptosis of SCC-9 cells, and its mechanism may be related to activation of MAPK/ERK signaling pathway and phosphorylation of downstream caspase signaling factors