[Abstract] Objective: To investigate the effect of polyadenosine diphosphate ribose polymerase 1 (PARP1) on the proliferation and 5-FU resistance of gastric cancer cells and its potential mechanism. Methods: The tumor tissues and corresponding paracancerous tissues of 72 patients with gastric cancer who were treated in Central Hospital of Enshi Tujia and Miao Autonomous Prefecture from May 2018 to December 2019 were collected. AGS cells were transfected with siFUT8 to knock down FUT8 gene expression. qPCR and immunohistochemistry were used to detect the expression of PARP1 in gastric cancer and adjacent tissues. CCK-8, flow cytometry, and colony formation assay were employed to detect the effects of AG14361 on the proliferation, apoptosis and colony formation of AGS cells. MTT assay was used to detect the effect of AG14361 on the 5-FU sensitivity of gastric cancer cells. The overall distribution of differential genes in AGS cells treated with AG14361 was analyzed by mRNA sequencing, and related signaling pathways were analyzed by KEGG enrichment. qPCR and WB were used to detect the expression of α-1,6-fucosyltransferase (FUT8) in AGS cells and the interference effect of FUT8. CCK-8, flow cytometry, and colony formation assay were employed to detect the effects of AG14361 on the proliferation, apoptosis, and colony formation of AGS cells disturbed by siFUT8. Results: Compared with paracancer tissues, PARP1 expression was significantly increased in gastric cancer tissues (P<0.001). AG14361 can significantly inhibit the proliferation and colony formation of AGS cells, thus promoting the apoptosis of AGS cells (all P<0.01). AG14361 treatment reduced the IC50 of 5-FU against gastric cancer cells, especially against AGS cells, with IC50 decreased by more than 60%. mRNA sequencing results showed that FUT8 was a key glycosyltransferase of AG14361 in inhibiting the proliferation of AGS cells (P<0.05). Compared with the siNC group, treatment of AG14361 with IC50 significantly reversed the promotion of AGS cells proliferation caused by inerference with FUT8, promoted apoptosis and BAX protein expression, decreased Bcl2 protein expression and inhibited the increase in AGS cell colony formation caused by interference with FUT8 (all P<0.01). Conclusion: PARP1 can promote malignant transformation of gastric cancer cells by regulating N-glycosyltransferase FUT8. AG14361 can enhance the chemotherapy sensitivity of 5-FU, and PARP1 may become a potential target for gastric cancer treatment.