To investigate the efficacy of fluorouracil (FU) combined with paclitaxel (PTX) and oxaliplatin (OXA) as the first-line treatment for advanced gastric signet ring cell carcinoma (SRCC) and its influence on human epidermal growth factor receptor 2 (HER-2) expression. We collected one hundred and sixty-eight patients with advanced gastric SRCC, including 87 patients treated with FU combined with PTX and OXA as the study group (SG) and 81 patients treated with FU combined with OXA as the control group (CG). We compared indicators such as efficacy and adverse reactions after treatment between the two groups and also detected serum HER-2 expression pre- and post-treatment. The incidence of adverse reactions differed insignificantly between SG and CG (P > 0.05). SG presented a notably higher objective response rate (ORR) and disease control rate (DCR) than that of CG (P < 0.05). After treatment, the serum HER-2 expression level of patients in both groups decreased significantly (P < 0.05), and that in SG was significantly declined compared to CG (P < 0.05). HER-2 was negatively correlated with the efficacy of both SG and CG. The 1-year survival rate in SG (29.89%) was significantly higher than that in CG (16.05%) (P < 0.05). The median OS and PFS were higher in DG than that in CG (P < 0.05). FU combined with PTX and OXA can effectively improve the efficacy of first-line treatment for advanced gastric SRCC while reducing HER-2 expression, without increasing the adverse reaction rate. This treatment is worthy of clinical promotion.