BACKGROUND Circular RNA (CircRNA) and HBx genes separately play essential roles in the occurrence and development of hepatitis B (HBV)-related hepatocellular carcinoma (HCC). However, whether HBx expression in HCC is co-related to differential circRNA patterns remains unknown. METHODS HCC cell lines with HBx overexpression (HepG2 H6679) and empty vector control (HepG2 H5298) were successfully constructed. The high-throughput second-generation transcriptome sequencing technology (RNA-seq) was employed to sequence the two cell lines, and the selected circRNAs were verified by qPCR (quantitative real-time PCR). The differentially expressed circRNAs were analyzed. Bioinformatics analyses, including clustering, differential expression, GO analysis, and KEGG pathway, were performed. Target Scan and Miranda software were employed to predict miRNAs corresponding with circRNAs. RESULTS We identified 1120 circRNAs upregulated and 1447 circRNAs downregulated in HepG2 cell lines with HBx overexpression compared to its control. We selected 36 circRNAs with significant differences (also consistent with log2fold change absolute value ≥ 1.0 or P ≤ 0.05) displayed by cluster analysis and then performed qPCR validation. Among them, 15 circRNAs (hsa_circ_0005603, hsa_circ_0004448, hsa_circ_0006845, hsa_circ_0064654, hsa_circ_0006460, hsa_circ_0045350, hsa_circ_0000824, hsa_circ_0005227, hsa_circ_0067991, hsa_circ_0064656, hsa_circ_0005224, circRNA11716, circRNA759, circRNA14848 and circRNA13751) are consistent with sequencing results. Hsa_circ_0005603 and hsa_circ_0006845 showed significant differences and were chosen for further study. GO analysis shows that many target genes are involved in biological processes, cellular components, and molecular functions. Nearly 193 target genes were enriched on KEGG pathways analysis. Actin cytoskeleton regulation, tight junction, and FoxO signaling pathway are among the top three pathways involved in most genes. We predicted that hsa_circ_0005603 might interact with micro-RNAs, including miR-182-5p, hsa-miR-27a-3p, hsa-miR-98-5p, and hsa-miR-198, that might thereby regulate downstream genes involved in tumor progression. Similarly, hsa_circ_0006845 was predicted to be referred to HBV-related HCC by acting as a sponge for hsa-miR-106a-3p and hsa-miR-198. Furthermore, we discovered two novel circular RNAs (circRNA11716 and circRNA13751) which might be involved in HCC occurrence. CONCLUSION In this study, we comprehensively explored the differentially expressed circRNAs in HepG2 cells with different HBx expression, and our results indicate that hsa_circ_0005603, hsa_circ_0006845, and novel circular RNAs (circRNA11716 and circRNA13751) might play an important role in HBV-related HCC, deserving further research.