Once diabetes is not effectively controlled by diet and exercise therapy alone, medication intervention is required. Here we are talking about the effective sequential treatment program according to the grade of diabetes. 1.Grade treatment plan: for the key link of insulin resistance, choose a drug that can improve insulin resistance, these drugs include biguanides and thiazolidinediones insulin sensitizers. Indications: Early stage patients with normal or high insulin levels. Ineffective can enter level 2 treatment regimen. Level 2 treatment plan: Combined application of insulin sensitizers and postprandial glucose regulators; after ineffective, level 3 treatment plan can be chosen. Level 3 treatment plan: insulin sensitizer and postprandial glucose regulator, together with insulin-producing agents (including sulfonylurea glimepiride or nonsulfonylurea nateglinide, etc.). Indication: Patients whose islet function is reduced to 1/2 of normal. After ineffective, they can enter level 4 treatment regimen. Level 4 treatment plan: insulin supplementation therapy, that is to say, the combination of oral hypoglycemic drugs and insulin, the most commonly used plan is to take oral hypoglycemic drugs during the day and inject once at night before bedtime with medium-acting (or long-acting) insulin. Applicable: Patients whose islet function is reduced to 1/3 of normal. 5.Grade treatment plan: stop all insulin-producing agents and use insulin replacement therapy. Applicable: Diabetic patients with complete islet failure can take several times a day (3 to 4 times) subcutaneous injection or insulin pump intensive treatment. Combination principle: In order to protect the function of pancreatic islets and reduce the side effects of drugs, when a drug used to half of the maximum therapeutic amount still can not make good control of blood sugar, it is recommended to use the combination of two (or more) drugs early, rather than advocating the addition of a drug to the maximum amount.