Abstract: Hepatocellular carcinoma (HCC) is the most common pathological type of primary liver cancer, with high fatality rate. The pathogenesis of HCC is complex, and the specific occurrence and development mechanism is still in the exploratory stage. CircRNA is a special endogenous noncoding RNA and mainly participates in the regulation of gene expression at the transcriptional and posttranscriptional levels. By regulating gene transcription, it acts as a molecular sponge of miRNA, participates in protein translation, and interacts with RNA binding protein (RBP). CircRNA is involved in the occurrence and development of HCC. Its abnormal expression in HCC cells is related to the pathological characteristics of HCC tissue, regulates the expression of downstream target genes, miRNA and proteins, participates in the proliferation, migration, invasion and apoptosis of HCC cells, and regulates tumor microenvironment and signal pathways, suggesting that circRNA may be a potential novel biomarker and therapeutic target for the diagnosis and prognosis of HCC. This paper reviews the biological mechanism of circRNA, its role in HCC, and research progress in diagnosis and treatment.