Watermelon has a glycemic index of 72, making it a high glycemic index food. Glycemic Index (GI) reflects the speed and ability of a food to raise blood glucose compared to glucose. Glycemic index greater than 70 is considered as high GI food, 55-70 is considered as medium GI food and less than 55 is considered as low GI food. The glycemic index of watermelon is 72, indicating that it has a high glycemic index and is a high GI fruit. In addition, watermelon has a high sugar content and is not recommended for diabetic patients with unstable blood sugar. After blood glucose control is stabilized, watermelon can be eaten in small amounts, consulting the attending physician if necessary. In daily life, patients with high blood glucose are recommended to have a low-salt, low-fat and low-sugar diet, eat more fresh vegetables and fruits, and take regular aerobic exercise, all of which can help control blood glucose. Meanwhile, patients should monitor their blood glucose level regularly and seek medical advice if they feel unwell.