Background: Breast cancer is the most common female cancer in the world. Many scholars have devoted themselves to elucidating the pathogenesis of Breast cancer. In the past, dCTP pyrophosphatase 1 (DCTPP1) was thought to be overexpressed in several cancers. However, The mechanism by which DCTPP1 is regulated by non-coding RNA in Breast cancer and its relationship with immune infiltration have not been elucidated.Results: In this study, reliable databases from the Cancer Genome Atlas (TCGA) and Gene Expression Integration (GEO) showed that the expression of DCTPP1 in Breast cancer tissues was higher than in normal tissues. Bioinformatics analysis showed that DCTPP1 was negatively correlated with the expression of hsa-miR-125b-5p in BRCA,The expression of LncRNA LGALS8-AS1 is positively correlated with the expression of DCTPP1, and negatively correlated with the expression of hsa-miR-125b-5p. Therefore, we speculate that lncRNA LGALS8-AS1 promotes tumor progression through sponge hsa-miR-125b-5p and maintains the overexpression of DCTPP1 in Breast cancer. The survival analysis of 3 genes showed that the overexpression of DCTPP1 and LGALS8-AS1 is related to the poor prognosis of patients. By analyzing the relationship between DCTPP1 and immune infiltration, we found that the high copy of DCTPP1 is related to the infiltration of CD8+ T cells, and the high expression of DCTPP1 is related to the infiltration of CD4+ T cells in basal-like Breast cancer. DCTPP1 is positively correlated with the expression of immune checkpoint B7-H3.Conclusion: LNC LGALS8-AS1 can upregulate DCTPP1 by sponging with hsa-miR-125b-5p. DCTPP1 can be used as a new prognostic marker for B7-H3 antibody treatment of breast cancer.