Background: Copper dysregulation has been linked to liver disease, cardiac dysfunction, neuropathy, and anemia. Previous investigations have been undertaken to demonstrate the impact of cuproptosis-related genes (CRGs) on the poor prognosis of hepatocellular carcinoma (HCC), while the prognostic significance and beneath molecular basis of DNA-methylation sites located in CRGs remain unknown. This study aims to identify CRG-located DNA-methylation sites linked to patient prognosis and establish a novel prognostic biomarkers combination for CRG-located DNA-methylation signature. Methods: The prognostic biomarkers combination was established through multivariate-Cox-regression after CRG-located DNA-methylation sites tied to the outcome of patients emerged by univariate-Cox-regression. The correlation between signature and immune cell infiltration levels, immune-checkpoint-associated genes was analyzed using spearman correlation and the difference was contrasted between different groups utilizing the Mann-Whitney-U test. Real-time quantitative methylation-specific polymerase chain reaction (RT-qMSP) was used to identify gene methylation. Results: A novel prognostic biomarkers combination for CRG-located DNA-methylation signature was established. Subsequently, the independence of this methylation signature from clinical features and its correlation with immune infiltrative and immune checkpoints in HCC were also investigated. DNA methylation alterations can influence the onset, development, and treatment of various tumors by regulating the transcription of corresponding genes. Our analysis found that cg05706061 contained in prognosis signature was located in the promoter region of the cuproptosis-related gene SLC31A2. The DNA-methylation level of cg05706061 demonstrated significantly different between tumor and normal tissue, and significantly correlated with the expression of SLC31A2. We further investigated the promoter methylation status of SLC31A2 by qMSP, the result showed that the DNA-methylation level of SLC31A2 in HCC cell lines were significantly decreased compared with normal liver cells. Conclusions: Our findings reveal possible mechanisms of CRG-located DNA-methylation on the advancement of HCC and offers new perspectives for prognostic assessment and treatment options.