Background The aim was to analyze the association between the TME and NER factors, and further to explore the effect of miRNAs on the gene expression of NER factors. This was to reveal the regulatory mechanism between DNA damage repair and the TME of GC.Methods ESTIMATE and CIBERSORT-based algorithms were used to assess the relationship between DDR scores and infiltration of immune cells in a TCGA-GC cohort. Eight databases were used to predict miRNAs regulating NER factors and qRT-PCR experiments were used to validate the regulatory relationship between key miRNAs and NER factors.Results (1) GC patients were divided into two groups with high and low DDR capacity; (2) DDR score was correlated with the proportion of immune cell infiltration; (3) DDR score was negatively correlated with FOXO3A but positively correlated with PDL1; (4) GO functional enrichment analysis between DDR subgroups was mainly about rRNA; (5) has-miR-3163, has-miR-944, has-miR-590-3P, miR-551b-5p,has-miR-548c-3p targeted many NER genes; (7) NER factors, RAD23B, POLR2A, ERCC8, CUL3, CUL5, GTF2H5, ERCC4 POLR2H, POLR2D, and GTF2H1, are predicted to be regulated by upstream miRNAs, thereby influencing the immune microenvironment and even the progression of GC.Conclusions NER factors may influence GC progression by working on the TME.