Circular RNA (circRNA) is a type of covalently closed non-coding RNA that may regulate gene expression in eukaryotes. The recent application of high-throughput RNA sequencing and bioinformatics approaches has revealed a large number of circRNAs in human cells. Emerging evidence indicates that many circRNAs have tissue and timing specificity and are linked to physiological development and various diseases. circRNAs have also been shown to be enriched and stable in extracellular fluid, indicating the potential of circRNAs as cancer biomarkers. Gastric cancer is one of the most common human cancers，and its the third most common cancer-related cause of death worldwide. Despite many advances in the diagnosis and treatment of this disease, the prognosis of patients with GC remains poor, with a 5-year overall survival of less than 30% in most countries. Therefore, the discovery of new molecular mechanisms and therapeutic targets that may control the severity of GC and present a predictive value for prognosis is of great importance. CircRNA has been increasingly studied in gastric cancer in recent years and plays an important role in the development, diagnosis, treatment and prognosis of gastric cancer. Here, we summarize the current knowledge about circRNAs, including their production mechanisms and general characteristics, biological functions, and their research progress in gastric cancer and problems in the research.