Gestational diabetes is one of the common obstetric complications, and timely screening for diabetes during pregnancy is an important way to prevent and treat gestational diabetes. The glucose tolerance test is the most commonly used clinical screening test for gestational diabetes. The glucose tolerance test is a test that measures the fasting blood glucose of a pregnant woman and her tolerance to elevated blood glucose. The glucose tolerance test is usually performed between 24 and 28 weeks of gestation. During the 24-28 weeks of gestation, pregnant women need to visit their local hospital on an empty stomach to have their fasting blood sugar measured first. A normal pregnant woman should have a fasting blood glucose of less than 5.1 mmol/L. After that, the pregnant woman should take 75 g of glucagon solution by mouth. The blood glucose level is measured 1 hour and 2 hours after the oral administration of the staphylococcus solution. In normal pregnant women, the blood glucose level should be less than 10 mmol/L 1 hour after the oral glucose solution and less than 8.5 mmol/L 2 hours after the oral glucose solution. if the pregnant woman misses the best time for the test at 24-28 weeks of gestation, a glucose tolerance test can also be performed after 28 weeks. Alternatively, fasting blood glucose can be measured regularly to monitor changes in blood glucose. In summary, the glucose tolerance test is the most important way to screen for gestational diabetes during pregnancy, and it is recommended that pregnant women have a glucose tolerance test at 24-28 weeks of gestation.