Gestational diabetes mellitus (GDM) is the most common pregnancy-related disease that increases the risk of metabolic disorders for the pregnancies and their offspring. GDM could be effectively prevented by early diagnosis and timely treatment.120 patients with GDM and 108 gestational week-matched pregnancies with normal glucose tolerance (NGT) were enrolled in our study. Their blood samples were collected, and demographic characteristics were analysed.Compared to NGT pregnancies, patients with GDM had increased the secretions of interleukin (IL)-33, soluble suppression of tumorigenicity 2 (sST2), IL-6 and tumour necrosis factor-α (TNF-α) in their plasma with elevated homeostatic model assessment (HOMA). Moreover, IL-33/sST2 was positively correlated with HOMA, IL-6 and TNF-α levels in the plasma of patients with GDM respectively.IL-33/sST2 might serve as a novel potential biomarker for early diagnosis of GDM.