Abstract: Objective To observe the effect of one-day outpatient management to patients with gestational diabetes mellitus(GDM).Methods Totally 200 patients with GDM were recruited from Oct. 2019 to Oct. 2020. They were randomly divided into the observational group and the control group. There are 100 cases in each group. One-day outpatient management team was established.The observational group received health education, exercise instruction and diet control. The control group was given routine care.Compliance behavior, knowledge awareness, blood glucose level and the incidence of maternal and infant complication were compared between the two groups.Results The compliance behavior, knowledge awareness and blood glucose level of the observational group were better than the control group, while incidence of maternal and infant complication in observational group was less than that in the control group(P＜0.05).Conclusion One-day outpatient management helps patients with GDM to control blood glucose level and improve pregnancy outcome. It is an effective mode to achieve group management.