Urine glucose 3 + positive is the result of routine urine test, which may be caused by diet or diabetes. 1. Diet: If the patient eats a lot of high sugar foods, such as milk tea, cream cakes, candies, etc., before the routine urine test, it will cause too much sugar in the urine, which will lead to the phenomenon of 3 + positive urine glucose when the patient undergoes the routine urine test. 2. Diabetes mellitus: The cause of diabetes mellitus is not yet clear, and it is considered to be caused by a combination of genetic or environmental factors. Patients with diabetes have no obvious clinical symptoms in the early stage, and those who have symptoms will have symptoms such as excessive eating, drinking and urination, which will also lead to 3+ positive glucose results when patients undergo routine urine testing. When patients have 3 + positive glucose in urine routine test, it may be caused by diet and does not need treatment, and it is recommended that patients should go to the hospital for review in time. If it is caused by diabetes mellitus, the patient should go to the hospital in time and follow the doctor’s instructions for treatment.