Establish a cohort study to describe the characteristics of gastric emptying in patients with type 1 diabetes, and adjust the timing of insulin injection during meals to improve blood glucose fluctuations according to the speed of gastric emptying.

1. T1DM that met the inclusion criteria was tested with baseline blood routine, biochemical and complication screening, and FGM monitoring for 14 days (patient blindness) on the basis of the original regimen (insulin pump or basic insulin combined with fast-acting insulin before three meals); A stable diet should be maintained before and during the study.

1. T1DM that met the inclusion criteria was tested with baseline blood routine, biochemical and complication screening, and FGM monitoring for 14 days (patient blindness) on the basis of the original regimen (insulin pump or basic insulin combined with fast-acting insulin before three meals); A stable diet should be maintained before and during the study.
2. On the 7th day of FGM monitoring, 13C-GEBT examination was performed on an empty stomach;
3. Starting from day 8, patients were divided into groups according to the comparison of gastric emptying T50 with pre-experimental healthy people. Group A, patients with rapid gastric emptying, adjusted the time of fast-acting insulin injection to 15 minutes before meals; Group B, patients with slow gastric emptying, adjusted the time of fast-acting insulin injection to 15 minutes after eating.
4. FGM monitoring was completed on the 14th day and the study was concluded. 2. On the 7th day of FGM monitoring, 13C-GEBT examination was performed on an empty stomach;

3. Starting from day 8, patients were divided into groups according to the comparison of gastric emptying T50 with pre-experimental healthy people. Group A, patients with rapid gastric emptying, adjusted the time of fast-acting insulin injection to 15 minutes before meals; Group B, patients with slow gastric emptying, adjusted the time of fast-acting insulin injection to 15 minutes after eating.

4. FGM monitoring was completed on the 14th day and the study was concluded.

Inclusion Criteria:

• 1.Volunteer and sign subject informed consent prior to the trial.

  2.Patients with type 1 diabetes, aged less than 70 years, 7%≤HbA1c≤9.0%.

  3.There were no acute complications such as diabetic ketoacidosis and diabetic hypertonic syndrome.

  4.Subjects were able and willing to undergo 14-day scanning blood glucose monitoring, diet and exercise routine.

Exclusion Criteria:

• 1.Patients with severe gastrointestinal symptoms, history of gastrointestinal disease, surgical history, or impaired liver and kidney function.

  2.Patients who have used drugs that affect gastrointestinal function or appetite in the last week.

  3.History of drug abuse and alcohol dependence within the past 5 years.

  4.Systemic hormone therapy was used in the last three months.

  5.Patients with poor compliance, irregular diet and exercise.

  6.Patients with infection and stress within four weeks.

  7.Patients who could not tolerate 14-day scanning blood glucose monitoring.

  8.Patients who are pregnant, nursing or intending to become pregnant.

  9.Any other obvious condition or comorbidities determined by the investigator: such as serious cardiopulmonary disease, endocrine disease, neurological, neoplastic, other pancreatic disease, history of mental illness.