Objective：To investigate the expression of calcium binding protein S100A16 in gastric cancer tissues and cells and its effect on the proliferation，migration and invasion of gastric cancer cell SGC-7901. Methods：Immunohistochemical staining was used to detect the differential expression of S100A16 in 8 pairs of gastric cancer and corresponding adjacent tissues. S100A16 overexpression plasmid and empty plasmid，interference plasmid and empty vector were transfected into human gastric cancer cell line SGC-7901 respectively，and the expression of S100A16 in each group was detected by Western blot. SRB staining and colony formation assay were used to detect the proliferation of cells in each group. Scratch test was used to detect the migration ability of cells in each group. Transwell assay was used to detect the invasive ability of each group. Results：The expression of S100A16 in gastric cancer tissues and gastric cancer cells were significantly higher than that in corresponding paracancerous tissues and normal gastric epithelial cells. SRB staining and colony formation assays showed that overexpression of S100A16 increased the proliferation of SGC-7901 cells and knocked down the proliferation of S100A16 cells. Scratch and Transwell experiments showed that overexpression of S100A16 increased SGC-7901 cell migration and invasiveness，while knockdown of S100A16 decreased. Western blot analysis showed that the expression of YBX-1 in SGC-7901 cells transfected with S100A16 over-expression plasmid was significantly increased compared with the control group. Co-immunoprecipitation experiments showed that S100A16 bound to YBX-1 in gastric cancer cell line SGC-7901. Conclusion：The expressions of S100A16 in gastric cancer tissues and cells are significantly up-regulated. The abnormal expression of S100A16 in gastric cancer may be due to the interaction with YBX-1，thereby promoting the proliferation，migration，invasion of gastric cancer cells and affecting the occurrence and development of gastric cancer.