Background/Aim: Gestational diabetes mellitus (GDM ), a metabolic disease of pregnancy, is a common complication of perinatal period, the incidence of which is increasing year by year. Among them, the incidence of metabolic diseases such as GDM was significantly increased in the advanced maternal age (AMA). The aim of this study was to study the intestinal flora, immune and inflammatory parameters of GDM patients, especially the AMA with GDM. Methods: Total 111 pregnant women who had regular prenatal examination and delivery in our hospital from January 2017 to June 2018 were selected. All participants were divided into normal group (n=50), GDM patients (n=61): normal maternal age (NMA) group (n=32) and AMA group (n=29). The total DNA of fecal samples was extracted, the V4 gene was amplified by 16S rRNA, and sequenced by Illumina platform. The blood supernatant of all cases was isolated to detect inflammation and immune markers. Results: Compared with Non-GDM group, the levels of hs-CRP, TNF-alpha and IL-6 were significantly higher while IL-10 was markedly lower in AMA and NMA with GDM group, and the highest in AMA group. Moreover, the levels of T leukomonocyte subgroup CD3, CD4 and the ratio of CD4/CD8 were greatly reduced in AMA and NMA patients, especially in the AMA group, and the level of T leukomonocyte subgroup CD8 was greatly enhanced in GDM patients. Compared with Non-GDM group and NMA group, the abundance of Fusobacteria, Verrucomicrobia, and Actinobacteria was relative higher on phylum level in AMA group. Conclusion: Analysis of immune and inflammatory indicators and understanding of intestinal microbiome characteristics can be used as potential screening tools and treatment targets in GDM cases, especially in the AMA with GDM patients.