Hepatocellular carcinoma is one of the most common malignant tumors worldwide, posing a great threat to human health and life. Despite the tremendous progress in understanding the origin and molecular characterization of hepatocellular carcinoma, there are still fewer therapeutic options that can significantly increase the survival rate and improve the quality of life of patients. Protein post-translational modifications (PTMs) are regulatory mechanisms for the regulation of protein activity, localization, expression, and interactions with other cellular molecules that induce changes in protein properties and functions. More and more studies have demonstrated that PTMs and immunotherapy play an important role in the development of hepatocellular carcinoma, even in the immunosurveillance of hepatocellular carcinoma and the treatment and prognosis of hepatocellular carcinoma patients. Traditional types of PTMs include phosphorylation, glycosylation, methylation, and ubiquitination. Phosphorylation affects cancer development and progression by regulating tumor cell proliferation, invasion and metastasis, and inhibiting apoptosis. There are two main types of glycosylation: O-glycosylation and N-glycosylation. Abnormal glycosylation not only promotes the proliferation and metastasis of hepatocellular carcinoma cells, but also plays an important role in immune recognition and immune escape. Common methylation modifications include DNA methylation, RNA methylation and histone methylation. Among them, histone methylation , as an important epigenetic regulatory mechanism, is of great theoretical and practical significance for understanding the mechanism of hepatocellular carcinoma as well as carrying out the corresponding prevention and immunotherapy. Ubiquitination plays an important role in the localization, metabolism, function, regulation and degradation of proteins, and it is regulated at different levels by ubiquitin-activating enzyme (E1), ubiquitin-conjugating enzyme (E2), ubiquitin-conjugating enzyme (E3), and a series of deubiquitinating enzymes (DUBs) and is closely related to hepatocellular carcinoma immunotherapy. This paper begins with a brief overview of the importance of post-translational modification of proteins, discusses the importance of these traditional types of PTMs in hepatocellular carcinoma immunotherapy, and summarizes the most recent applications of these approaches in hepatocellular carcinoma in order to explore the mechanism of action of PTMs in hepatocellular carcinoma immunotherapy. Second, we summarize the finding that programmed death-ligand 1 (PD-L1) is associated with a variety of conventional types of PTMs, that in-depth study of the mechanisms regulating PD-L1 expression in tumor cells is expected to improve therapeutic efficacy, and that targeting PD-L1 in PTMs is expected to be a new field for exploring hepatocellular carcinoma immunotherapy in the future. Finally, we discuss the current status of research on PTMs for hepatocellular carcinoma immunotherapy and provide new insights and future research directions. In addition to the traditional types of PTMs, multiple novel PTMs have also been identified in published research reports, while the relationship between novel PTMs and hepatocellular carcinoma and the types of post-translational modifications to other undiscovered proteins are still poorly understood, and future research will be focused on a more comprehensive knowledge and understanding of PTMs as well as on exploring new types and mechanisms of PTMs. Overall, further investigation of the role of PTMs in tumor immunity could help to discover new biomarkers and to develop more effective and personalized cancer immunotherapies and targeted therapies, expanding our understanding of cancer biology.