Abstract: In recent years, the prevalence of gestational diabetes mellitus (GDM) has significantly increased, leading to various adverse outcomes for mothers and their offspring. Early diagnosis and good blood glucose control can significantly improve pregnancy outcomes. Currently, the diagnosis of GDM mainly relies on the oral glucose tolerance test (OGTT), but there are many limitations in clinical application. The new biological marker glycosylated CD59 is a glycosylation product of complement regulatory proteins that can stably exist in body fluids and is linearly related to blood glucose levels, which has the advantages of simple testing and good reproducibility, and has been developed into a stable reagent kit. It has shown good value in the early diagnosis, standard diagnosis, and prediction of pregnancy outcomes of GDM.