Circular RNAs (circRNAs) in malignant tumors has aroused increasing attention. We combined the results of three sets of circRNA sequencing from the GEO database (GSE83521, GSE93541 and GSE131414) to screen out the most potential hsa_circ_0001364 in gastric cancer (GC). The expression level of plasma hsa_circ_0005480 in GC patients was significantly higher than that in patients with benign gastric lesions and healthy donors, and this high expression of hsa_circ_0005480 was correlated with tumor differentiation, nerve or vascular invasion, and cytokeratin (CK) positivity. Hsa_circ_0005480 performed well in distinguishing GC patients from healthy donors, with an area under the ROC curve (AUC) of 0.784. Combination of hsa_circ_0005480 with traditional laboratory metrics resulted in the maximum AUC, showing better sensitivity and accuracy than the standalone application of these metrics. Compared with newly diagnosed GC patients, the expression of plasma hsa_circ_0005480 was low in GC patients treated with chemoradiotherapy or surgery, and hsa_circ_0005480 usually decreased dynamically around one week after surgery. Finally, hsa_circ_0005840 was mainly located in the cytoplasm, implying that its potential to serve as a competing endogenous RNA or miRNA sponge. These results suggest that hsa_circ_0005480 has the potential to be a marker for auxiliary diagnosis and prognostic evaluation of GC.