Inclusion Criteria:
1. Age ≥ 65 years ;
2. Autologous degenerative aortic stenosis（evaluated by echocardiography: transaortic valve pressure gradient ≥40mmHg , or transaortic valve blood flow rate ≥4m/s, or aortic Valve area\<1.0cm2, or AVA \<0.5cm2 /m2）
3. Patients with aortic annulus size≥17.5mm and ≤29mm (echocardiography measurement);
4. The diameter of the ascending aorta of the patient was \< 45mm.
5. Appear obvious symptoms caused by aortic stenosis, NYHA class Ⅱ to IV;
6. Subject or subject's legal representative have been informed of the nature of the study, agrees to participate and has signed the approved consent form.
7. Subjects are willing to accept all clinical follow-up.
8. The cardiologist and cardiac surgeon evaluated the subject as unsuitable for surgical treatment (the risk of death or irreversible complications within 30 days after operation is expected to be above 50% , or contraindicated comorbidities such as prior chest radiotherapy, liver failure, diffuse severe calcification of the aorta, extreme weakness, etc.). Or Moderate or higher surgical risk (STS score ≥ 4%).
Exclusion Criteria:
1. defined as Q-wave myocardial infarction or non-Q-wave myocardial infarction with CK-MB level ≥ 2 times the upper limit of normal value and / or Tn increase.
2. Subjects with congenital unicuspid, without calcification.
3. Any therapeutic or traumatic cardiac surgery within 30 days (within 3 months in case of drug-eluting stents implantation)
4. The patient's heart has been implanted with other artificial heart valves, artificial rings, or severe mitral annulus calcification (MAC), severe (\> 3 +) mitral insufficiency.
5. Hematological abnormalities, including leukopenia (WBC\<3×109/L), acute anemia (HB \<90g/L), thrombocytopenia (PLT\<50×109/L), bleeding constitution and coagulopathy ；
6. Subjects with hemodynamic instability, requiring continuous mechanical heart assistance.
7. Subjects who need emergency surgery for any reason;
8. Hypertrophic cardiomyopathy with or without obstruction;
9. Severe left ventricular dysfunction, left ventricular ejection fraction (LVEF) \<20%;
10. The echocardiogram indicates the presence of a thrombus or vegetation;
11. A history of active peptic ulcer or upper gastrointestinal bleeding within 3 months;
12. Are allergic to nickel titanium alloys or contrast agents, and cannot tolerate anticoagulation and antiplatelet therapy;
13. Cerebrovascular accident occurred within 6 months, including transient ischemic attack;
14. renal insufficiency(creatinine\> 3.0mg/dL) and/or end-stage renal disease requiring Renal dialysis;
15. Life expectancy\< 12 months;
16. Significant aortic diseases, including abdominal aortic or thoracic aortic aneurysm(defined as maximum lumen diameter \> 50mm, obvious distortion), atherosclerosis of the aortic arch(especially bulge with thickness \> 5mm or ulceration), narrowing of the abdominal or thoracic aorta(especially calcification and irregular surface), and severe curvature of the thoracic aorta;
17. The iliac-femoral artery cannot be inserted with a guide sheath of 22F or above, such as severely obstructed with calcification, severely tortuous or vessel diameter less than 6mm;
18. Screening participant who is participating in other drug or medical device clinical trials;
19. Active infective endocarditis or other active infections;
20. Anatomically, the approach or aortic root is not suitable for TAVR (such as a high risk of coronary artery occlusion).
21. Other conditions considered by the investigator to be inappropriate for participation in this clinical trial.
