To compare the accuracy of different blood glucose monitoring systems (CGM and FGM) in diabetic patients with insufficient islet function.

To compare the accuracy of different blood glucose monitoring systems (CGM and FGM) in diabetic patients with insufficient islet function with Venous Blood Glucose (including FGM early, middle and late, pre-and post-meal, high and low blood glucose).

Inclusion Criteria:

• volunteer to participate and be able to sign informed consent prior to the trial.
• patients with type 2 diabetes or type 1 diabetes, aged 18-80 years old.
• No acute complications such as diabetic ketoacidosis, diabetic hyperosmolar syndrome, etc.
• Subjects are able and willing to monitor peripheral blood sugar and regularity of diet and exercise.

Exclusion Criteria:

• Patients with insulin allergy.
• Impaired liver and kidney function with ALT 2.5 times higher than the upper limit of normal value; Serum creatinine was 1.3 times higher than the upper limit of normal.
• Drug abuse and alcohol dependence in the past 5 years.
• Systemic hormone therapy was used in the last three months.
• Patients with poor compliance and irregular diet and exercise.
• Patients with pregnancy, lactation or pregnancy intention.
• Any other obvious conditions or associated diseases determined by the researcher: such as severe cardiopulmonary diseases, endocrine diseases, neurological diseases, tumors and other diseases, other pancreatic diseases, history of mental diseases.