Abstract: The present study aimed to investigate miRNA expression patterns in hepatocellular carcinoma ( HepG2 ) and normol liver epithelial (LO2) cell lines. Another aim was to bioinformatically analyze as well as predict the target genes of miR-122a to provide both theoretical and experimental basis for gene therapy. Methods: The expression levels of miRNA-122a in HepG2 and LO2 cells were detected using the gene chip technology. The bioinformatic analysis of the target genes of miRNA-122a involved enrichment ( gene ontology ), signal transduction pathway enrichment, and protein interaction network analyses. Results: miRNA-122a expression significantly decreased in HepG2 cells, compared with LO2 cells. The number of miRNA-122a target genes was 1104. The functions of these target genes were enriched in carbohydrate biosynthesis, nucleotide metabolism, cytokine receptor binding, cell cycle, and other biological processes ( P < 0.001 ). The JAK-STAT signaling, Wnt signaling, MAPK signaling, ErbB signaling, and cell cycle signal transduction pathways were significantly enriched ( P < 0.001 ). Conclusion: miRNA-122a expression significantly decreased in HepG2 cells. Some of the predicted target genes of miRNA-122a were significantly enriched in tumor related with signaling pathways.