〔Abstract〕 Objective To investigate the regulatory mechanism of nucleotide excision repair(NER) in hepatocellular carcinoma(HCC). Methods Based on the expression levels of genes in the NER pathway, we performed molecular typing of HCC using the TCGA database. HCC cell lines were constructed through the knockdown of RNA binding motif protein 39(RBM39) using siRNA. HCC cell lines were constructed through the overexpression ofRBM39usingRBM39plasmid. Cells were treated with Indisulam, a reagent that induces RBM39 protein degradation. Western blot and real-time fluorescence quantitative PCR were used to detect the expression levels and changes of mRNA and protein of RBM39 and excision repair cross complementation group 1(ERCC1); flow cytometry was used to detect NER efficiency; CCK-8 assay was used to detect cell viability. Results HCC patients were categorized into three types—C1, C2, and C3—based on NER activity, with the C3 subtype showing the highest NER activity(P<0.000 1). In the groups transfected with RBM39 siRNA or treated with Indisulam, the NER repair efficiency decreased compared to the control group(P<0.01), the cell survival rate decreased(P<0.01), and both the mRNA and protein expression of ERCC1 were reduced(P<0.01). In contrast, in the RBM39 overexpression group, the mRNA and protein expression of ERCC1 were enhanced compared to the control group(P<0.01). Conclusion RBM39 may influence NER repair efficiency by regulating ERCC1 expression in HCC.