Diabetes that occurs during pregnancy only after normal glucose metabolism or underlying impaired glucose tolerance before pregnancy is called gestational diabetes; diabetes that was already present before pregnancy is called gestational diabetes. Most pregnant women with high blood glucose are in the first situation, and most of them can return to normal after delivery, but they still need to control their diet one year after delivery, otherwise they are prone to turn into ordinary diabetes. Gestational diabetes mellitus diagnosis of blood glucose value is higher than the normal level, but lower than the ordinary diabetes diagnostic standards, WHO diagnostic criteria (75gOGTT at 24-28 weeks of pregnancy): (1) fasting blood glucose <5.1mmol/ L and 1h blood glucose <10mmol / L and 2h blood glucose <8.5mmol / L, belong to the normal; (2) fasting blood glucose 5.1~6.9mmol / L or 1h blood glucose ≥10mmol/L or 2h blood glucose 8.5~11.0mmol/L, belong to gestational diabetes mellitus; (3) FPG ≥7.0mmol/L or 2h blood glucose ≥11.0mmol/L, belong to diabetes mellitus. Gestational diabetes mellitus is harmful to both mother and child, such as excessive amniotic fluid, miscarriage, gestational hypertension, macrosomia, fetal malformation, neonatal rostral distress syndrome, neonatal hypoglycemia, etc., which must be taken seriously. Pre-pregnancy overweight or obese people have a higher incidence, it is recommended to lose weight appropriately before planning a pregnancy. Once gestational diabetes mellitus, the first step is diet and exercise control, 1-2 weeks after the review, if the blood glucose control range is reasonable to continue to adhere to, if the blood glucose control is not good need to play insulin in a timely manner, play insulin need to be adjusted according to the blood glucose control situation in a timely manner insulin dosage, to prevent the emergence of hypoglycemia. Once diabetic ketosis occurs, intravenous insulin drip is needed. Ideal dietary control should be able to ensure the calorie and nutrient requirements of the mother and child, but also avoid the emergence of postprandial hyperglycemia or starvation ketosis. Therefore, once the diagnosis of gestational diabetes mellitus is confirmed, it is necessary to seek the help of a dietitian in a timely manner, so that the dietitian can assess whether the current diet and lifestyle habits are scientific and reasonable, so that the dietitian can formulate individualized dietary and lifestyle guidance suitable for themselves according to their own dietary habits and requirements.