Objective To explore the effect of the health education coordinated by medical staff and volenteers based on online-to-offline（O2O） conception on management effect during pregnancy and delivery outcome for patients with gestational diabetes mellitus. Methods Totally 140 patients with gestational diabetes mellitus were randomized into a control group and an observation group using a random number table, with 70 patients in each group.The control group were given routine health education, while the observation group received the health education coordinated by medical staff and volenteers based on O2O conception. The self-management behavior, self-management efficacy, blood glucose and delivery outcomes between the two groups were compared. Results After the intervention, the score of self-management behavior and self-management efficacy in the observation group were significantly higher than those of the control group, the blood glucose during pregnancy and glycosylated hemoglobin were significantly better than those of the control group, the rate of cesarean section and neonatal hypoglycemia were significantly lower than that of the control group （P＜0.05,P＜0.01）. Conclusion Implementation of the health education coordinated by medical staff and volenteers based on O2O conception for patients with gestational diabetes mellitus, is conducive to improving patients′ self-management behavior and self-management efficacy, controlling blood glucose and body weight during pregnancy, and reducing adverse pregnancy outcomes.