Abstract: Objective To explore the clinical effect of acarbose combined with metformin for patients with type 2 diabetes mellitus and its mechanism of action. Methods A total of 114 patients with type 2 diabetes were randomly divided into combined treatment group(n=58)and metformin group(n=56). The metformin group was treated with metformin, while the combined treatment group was given acarbose combined with metformin. After 3 months of treatment, serum inflammatory factors, T lymphocyte subsets, blood glucose control and incidence of adverse reactions were compared between the two groups. Results The levels of serum interleukin-6(IL-6), C-reactive protein(CRP)and tumor necrosis factor-α(TNF-α)in the combined treatment group were significantly lower than those in the metformin group(P<0.05), CD3⁺, CD4⁺, CD4⁺/CD8⁺ in the combined treatment group were significantly higher than those in the metformin group, and CD8⁺ was significantly lower than that in the metformin group(P<0.05). Fasting blood gluscose(FPG), fasting insulin(FINS), Hemoglobin A1c(HbA1c)and homeostasis model assessment of insulin resistance(HOMA-IR)in the combined treatment group were significantly lower than those in the metformin group(P<0.05). There was no significant difference in the incidence of adverse reactions between the two groups(P>0.05). Conclusion Acarbose combined with metformin can inhibit the inflammatory response of patients with type 2 diabetes mellitus, and regulate their cellular immune function and blood glucose level.