Db/dB mice, derived from autosomal recessive inheritance of C57BL / KsJ inbred strain, belong to the type 2 diabetes model. Leptin receptor point mutations lead to leptin signaling pathway disorders, causing obesity, insulin resistance, hyperglycemia, fatty liver and other symptoms in mice. One month after birth, Db/db mice began to binge eat and gain weight, which in turn produced hyperglycemia, high blood insulin, and elevated glucagon. Obvious obesity and fasting blood glucose increase can occur in 6 weeks. The water intake and urine volume increase, with the most obvious increase at 8-12 weeks, and complications such as diabetic nephropathy can occur. Db/db mice usually die within 10 months.