Fat in the body is metabolized in the liver, and if oxidation is incomplete, three substances are produced in the blood, acetoacetic acid, beta-hydroxybutyric acid and acetone, collectively known as ketone bodies. Normally, ketone bodies can be filtered out through the glomerular filtration membrane and appear in the urine, but the concentration of ketone bodies in normal blood is low and the level in urine is also very low and the test is negative. However, if for some reason the concentration of ketone bodies in the blood increases, after being excreted through the urine, urine ketone bodies are often positive. Usually, positive urine ketone bodies are seen in some cases such as diabetic ketoacidosis.1. Diabetic ketoacidosis: Positive urine ketone bodies are commonly seen in diabetic ketoacidosis, and the presence of ketonuria is a pre-indicator of diabetic ketoacidosis. For diabetes-induced positive urine ketone body, it mostly indicates that the body’s blood sugar level is high, while insulin is in a state of relative under-secretion. At this time, it is necessary to follow the doctor’s prescription to supplement sodium and potassium and appropriate amount of insulin after measuring blood glucose to correct the diabetic ketosis and prevent the appearance of ketoacidosis; 2, other: positive urine ketone body can also be seen in severe vomiting, long-term hunger, high fever, after strenuous exercise, etc., due to the impaired glucose metabolism produces positive urine ketone body, at this time, patients can appropriately supplement energy to correct the situation of positive urine ketone body. In addition, if a pregnant woman has positive urinary ketone bodies after a meal or after severe vomiting, she needs to consult a dietitian to develop a diet plan and adjust the diet structure.