Thus, through a variety of bioinformatics analyses and experiments, we confirmed that miR-137-3p played a tumor-suppressive role in gastric cancer, and its target gene COL5A1 could reversely sponge miR-137-3p to relieve its targeted inhibition of FSTL1, which may promote the progression of gastric cancer by affecting immune infiltration. The gene discussed is FSTL1; the disease is neoplasm.