〔Abstract〕 Objective To investigate the expression and biological function of circular RNA(circRNA) hsa＿circ＿0002938 in gastric cancer. Methods 45 pairs of tumor tissues and para-cancerous tissues from gastric cancer patients who underwent tumor reduction surgery at the hospital were collected. Human gastric cancer cells SGC-7901, BGC-823, HGC-27, MGC-803 and immortalized gastric mucosal epithelial cells GES-1 were routinely cultured. RT-qPCR was utilized to detect the expression of hsa＿circ＿0002938 in gastric cancer tissues and cells. Chi-square test was used to analyze its association with the clinicopathological characteristics of patients, and the Kaplan-Meier method was employed to assess the relationship between hsa＿circ＿0002938 expression levels and patient prognosis. The effects of hsa＿circ＿0002938 on the proliferation, migration and invasion abilities of gastric cancer cells were detected by CCK-8, scratch wound healing and Transwell assays. Bioinformatics was used to predict the miRNA and its downstream target genes that hsa＿circ＿0002938 might bind to. The competitive endogenous RNA regulatory network was constructed and the functions of the target genes were enriched. Results The expression of hsa＿circ＿0002938 in gastric cancer tissues and cells was much higher than that in para-cancerous tissues and GES-1 cells(P<0.05). By contrast, patients in the high hsa＿circ＿0002938 expression group had significantly shorter 2-year progression-free survival than that in the low expression group after surgery(P<0.01). Moreover, knocking down the expression of hsa＿circ＿0002938 reduced the proliferative, migratory, and invasive abilities of gastric cancer cells(P<0.05). Bioinformatics predictive analysis showed that hsa＿circ＿0002938 could bind to hsa-miR-342-3p and hsa-miR-503-5p. The downstream target genes of miRNA were involved in several cancer-related pathways, like mitogen-activated protein kinase(MAPK), hippo and Wnt signaling pathway. Conclusion Hsa＿circ＿0002938, which is highly expressed in gastric cancer tissues and cells, is closely associated with poor patient prognosis. Knockdown of hsa＿circ＿0002938 inhibits the proliferation, migration, and invasion abilities of gastric cancer cells. The study reveals the potential role of hsa＿circ＿0002938 in the progression of gastric cancer, offering new insights into its prevention and treatment.