Low insulin level is a decrease in insulin secretion, which is a hypoglycemic hormone secreted by the beta cells of the pancreas and is the only hypoglycemic hormone in the body. Under normal conditions, a dynamic balance is maintained between insulin and the antagonistic hormones of insulin. For example, glucagon, growth hormone and glucocorticoid are all blood glucose raising hormones, and they all belong to the antagonistic hormones of insulin in order for blood glucose to be maintained in dynamic balance. When the secretion function of pancreatic beta cells is reduced for various reasons, it will also lead to low insulin level, which will weaken the glucose-lowering effect of insulin and lead to abnormal glucose tolerance and even diabetes. Therefore, patients with low insulin levels need to review fasting, postprandial glucose and glycated hemoglobin to prevent the occurrence of diabetes. In addition, attention should be paid to avoid high sugar and high fat diet to avoid aggravating the functional burden of pancreatic β-cells and to protect the function of residual pancreatic β-cells.