Diabetes is a common metabolic disease, and insulin therapy is one of the most important tools in the treatment of diabetes. One of the necessary skills for clinicians to master insulin therapy is to precisely control the amount. This quantity includes not only the values of blood glucose, blood phosphorus and blood calcium, but also the precise control of the dose of drugs used, of which insulin is one of the most demanding. For this reason, we would like to present you a brief and concise point of dose calculation. 1.Estimated according to body weight Generally start with small dose, 0,3-0,4U/kg. 2.Estimated according to the severity of the disease The daily physiological secretion of insulin is 40-50U, so medium-sized cases can start with 4-10U; heavy cases 16-20U. The usage is subcutaneous injection 30min before meal, 3 times a day. 3.Estimated according to the urinary sugar excretion 1U of insulin for every 2g of sugar. 4.Estimated according to blood glucose concentration Blood glucose calculation formula: Insulin dosage = (blood glucose mmol/L-5,6 mmol/L) × 0,6 kg body weight ÷ 11,1. For example, if the patient weighs 60 kg and his blood glucose is 11,2 mmol/L, then the insulin dosage should be supplemented = (11,2-5,6) × 0,6 × 60 ÷ 111 = 18 U. Note, this is only an approximate estimate. It should be used in 2-3 times, and the first dose is 1/3-1/2 of the total. 5. The amount of insulin for three meals is generally morning>evening>midday. 6. Each insulin dose adjustment should be less than 20% of the original dose. It should be observed for 3-4 days before adjustment, and the dose is generally adjusted every 3-6 days in elderly patients.