〔Abstract〕 Objective To investigate whether exogenous calcium-binding protein A8/A9(S100 A8/A9) promotes the migration and invasion of oral squamous cell carcinoma(OSCC) cells CAL-27 and SCC-25 through Wnt/β-catenin. Methods CAL-27 and SCC-25 were cultured with S100 A8 and S100 A9 proteins respectively or together, and the expression of β-catenin was detected by Western blot. 20 μg/ml Wnt/β-catenin pathway inhibitor DKK-1 was added, the expression of β-catenin was detected by Western blot and qPCR; Transwell assay was used to compare the cell invasion and migration ability of normal control group, S100 A8/A9 protein added group, DKK-1 added group, and DKK-1 added and S100 A8/A9 protein recovery group; Western blot was used to detect the expression of c-Myc and cyclinD1. Results S100 A8 and S100 A9 could activate the Wnt/β-catenin pathway. Compared with S100 A8 and S100 A9 cultured separately, the expression of β-catenin in CAL-27 and SCC-25 cells was up-regulated with time when co-cultured, and the qPCR results were consistent with them; in the immunofluorescence experiment, changes in the expression of β-catenin were observed in the cytoplasm and nucleus of SCC-25 and CAL-27 cells, and the expression of β-catenin protein in SCC-25 and CAL-27 cells increased at 48 h(P<0.05). Adding DKK-1, Western blot and qPCR showed that the expression of β-catenin decreased(P<0.001); the number of cell migration and invasion in the S100 A8/A9 group was more than that in the blank group(P<0.001), the number of cells invading and migrating decreased in the DKK-1 inhibitor group, and the number of cells in the DKK-1 and S100 A8/A9 protein recovery group decreased, suggesting that DKK-1 could inhibit the promoting effect of exogenous S100 A8/A9 protein on the invasion and migration ability of SCC-25 and CAL-27 cells, and the difference was statistically significant(P<0.001); adding Wnt/β-catenin pathway inhibitor DKK-1, Western blot experiments showed that the expressions of key molecules c-Myc and cyclinD1 in the Wnt/β-catenin pathway decreased(P<0.001). Conclusion Exogenous S100 A8/A9 can promote the invasion and migration of SCC-25 and CAL-27 cells by activating the Wnt/β-catenin signaling pathway.