Background: To investigate the short-term efficacy of the modified FOLFIRINOX regimen in the therapy of advanced pancreatic cancer and its effect on the immune function and serum tumor markers of subjects.Methods: 96 subjects with advanced pancreatic cancer were admitted to our hospital from January 2020 to January 2022. The subjects were divided into two subgroups according to different therapy plans, with 48 subjects in each subgroup. The control and observation subgroups were treated with gemcitabine (GEM), combined regimen and modified FOLFIRINOX regimen, respectively. In addition, at least three cycles of chemotherapy, the short-term curative effect, immune function, serum tumor marker level and adverse reaction between the two subgroups were compared. Results: Compared with the control subgroup, the disease control rate (DCR) in the observation subgroup was significantly higher (72.92% vs 52.08%) (p < 0.05). After chemotherapy, CD4+, CD4+/CD8+ ratio and serum immunoglobulin (Ig) A, IgG, IgM levels in the observation subgroup were significantly higher than those in the control group (p < 0.05). Versus the control subgroup, the level of CD8+ was significantly lower (p < 0.05). After chemotherapy, the levels of serum carbohydrate antigen 19-9 (CA19-9), carbohydrate antigen 125 (CA125), carcinoembryonic antigen (CEA) and macrophage inhibitory gytokine-1 (MIC-1) in the two subgroups decreased. Compared to the control subgroup, the levels in the observation subgroup were lower (p < 0.05). There was no notable difference in the incidence of adverse reactions between the two subgroups (37.50% vs 41.64%) (p > 0.05).Conclusions: Compared with the GEM combined chemotherapy scheme, the modified FOLFIRINOX scheme can improve the short-term efficacy of advanced pancreatic cancer, improve immune function, and reduce the expression of serum tumor markers. In addition, the patients can tolerate the FOLFIRINOX treatment scheme.