The Gastric Bypass Stent System is intended to be used in weight loss treatment for obesity in patients with a BMI ≥ 30 kg/m2. In this clinical investigation the Sponsor seeks to demonstrate the safety and performance of the Gastric Bypass Stent System for its proposed indication in weight loss treatment for obesity in the China.

Inclusion Criteria:

1. Aged 18-60 years, both male and female;
2. Obese patients with BMI ≥ 30 kg/m2, who are willing to be treated with Gastric Bypass Stent System or dietary intervention;
3. Patients with ASA I~II grade;
4. The patient understands the onjective of the trial and is volunteered to participate in the trial and has signed the Informed Consent Form (ICF).

Exclusion Criteria:

1. Have a weight loss of more than 4.5 kg in the past three months, or take weight-loss drugs in the past month;
2. Patients who used non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids in the past month;
3. Patients diagnosed with type 1 diabetes;
4. Patients with the function of islet β cell basically lost, C-peptide ≤ 1/2 of the normal low limit or low and flat C-peptide release curve under glucose load;
5. Patients with iron deficiency or iron deficiency anemia;
6. Patients with coagulation dysfunction who used aspirin and other anticoagulants in the past month;
7. Patients with severe liver and kidney dysfunction, and the serum creatinine concentration of greater than 180 μmol/L;
8. Patients with Class III heart function of NYHA or higher, or pulmonary dysfunction;
9. Patients who have undergone ERCP procedure, or have a history of cholecystitis or liver abscess;
10. Patients with duodenal ulcer, gastric ulcer or previous and existing pancreatitis;
11. Patients with gallstones (diameter ≥ 20 mm) with clinical symptoms;
12. Patients with thyroid dysfunction;
13. Patients with hemorrhage or potential hemorrhage in the digestive tract;
14. Patients with gastrointestinal tract anomalies, such as gastrointestinal tract atresia, or other conditions that would result in failed placement in the gastrointestinal tract;
15. Patients with a history of bowel obstruction or related diseases in the past year;
16. Patients with a history of systemic lupus erythematosus or scleroderma;
17. Patients with severe infections that are not controlled, not suitable for a procedure;
18. Patients with poor general condition and having endoscopic contraindications (as evaluated by the investigator);
19. Pregnant women or women having the plan for pregnancy;
20. Drug abusers or alcohol addicts or patients with uncontrollable mental illness;
21. Patients who participated in other clinical trials of drugs or medical devices before enrollment and do not reach the endpoint time limit;
22. Patients who participated in other clinical trials of drugs or medical devices before enrollment 3 months.
23. Patients with any other conditions evaluated by the investigators as unsuitable for participating in the trial.