Hepatocellular carcinoma (HCC) is a heterogeneous disease, and the complexity of its occurrence is associated with epigenetic modifications. Mammalian protein arginine methyltransferases (PRMTs) mediate epigenetic modifications of cells, and play an important role in the occurrence, development, treatment, and prognosis of hepatocellular carcinoma. PRMTs catalyze the monomethylation and (symmetric and asymmetric) dimethylation of arginine residues in histones and non-histone targets. PRMT family members, such as PRMT1, 2, 3, 4, 5, 6, 7, and 9, play different roles in hepatocellular carcinoma, involving cancer cell growth, metastasis, treatment, prognosis, etc. The research and development of selective and specific PRMT inhibitors are expected to provide new ideas and targets for the clinical treatment and improvement of the prognosis of hepatocellular carcinoma. This review focuses on the research progress on the role of PRMTs in hepatocellular carcinoma.