Type 1 diabetes is due to genetic, immune, and environmental factors. type 2 diabetes is due to genetic and environmental. Specialized types of diabetes are due to hyperthyroidism, infections, surgery and other factors. 1. type 1 diabetes occurs mainly due to a combination of autoimmune diseases, genetic and environmental factors. External factors (e.g. viral infections, chemical poisons, food, etc.) have an effect on genetically susceptible people and trigger a series of autoimmune reactions through T lymphocytes, causing damage to the beta cells on the pancreatic islets and a gradual decrease in the body’s insulin secretion, which in turn induces diabetes. 2. Type 2 diabetes is caused by a combination of genetic and environmental factors. Family members with a history of diabetes, or both of them have diabetes, will increase the chance of their children getting diabetes. type 2 diabetes has an almost 100% homozygosity rate among identical twins, but its onset and pathogenesis are highly variable due to the influence of different environmental factors. 3. Special types of diabetes, such as pancreatic β-cell gene defects, genetic defects in insulin action, pancreatitis, pancreatic tumors, acromegaly, hyperthyroidism, infections, surgeries, and other causes can lead to diabetes. Diabetes patients, usually pay more attention to diet and lifestyle habits, but also under the guidance of the doctor to use drugs or insulin to control blood sugar.