AbstractThe diagnosis and treatment of rheumatic valvular heart disease (RVHD) require substantial improvements. Studies found that circular RNAs (circRNAs) are involved in the progression of cardiovascular diseases. We screened target hsa_circ_0003748 by circRNA microarrays uploaded to a database. We used fluorescence in situ hybridization to determine the cellular location of hsa_circ_0003748. A dual‐luciferase reporter gene assay revealed that has_circ_0003748 might bind the miRNA miR‐577. In hVIC cells (an RVHD cell line), Cell Counting Kit‐8, Transwell, and flow cytometry assays measured proliferation, migration, and cell cycle and apoptosis, respectively. We found that hsa_circ_0003748 was localized in the cytoplasm; hsa_circ_0003748 promoted the proliferation and migration of hVIC cells, arrested the cell cycle in the G2/M phase, and inhibited apoptosis. These phenomena may result from hsa_circ_0003748 promoting RVHD after sponging miR‐577. Bioinformatic analysis revealed that hsa_circ_0003748 might affect RVHD progression by affecting transcription and the MAPK signaling pathway, the Ras signaling pathway, the cAMP signaling pathway, the Rap1 signaling pathway, and other signaling pathways.