Safety and Efficacy of TaurusOne® Transcatheter Aortic Valve Replacement System With Retrievable Delivery Catheter System

Inclusion Criteria: * Patients who are willing to participate and sign the informed consent and can cooperate with the whole trial process; * Age ≥70 years old; * Patients with severe calcified aortic stenosis confirmed by echocardiography (trans-aortic valve flow velocity ≥ 4.0m /s, or trans-active valvular pressure difference ≥40mmHg (1mmHg=0.133kPa), or aortic valve orientation area \< 0.8cm2, or effective aortic valve orifice the product index is \< 0.5cm2/m2); * Appear obvious symptoms caused by aortic stenosis, NYHA class Ⅱ or higher; * The cardiac team (at least two specialists in cardiovascular surgery) assessed the patient as unsuitable for routine surgery ; * The life expectancy of the patient after implantation of the prosthetic valve was evaluated by the cardiac team (at least two specialists in cardiovascular surgery) as more than one year; * Patients with aortic ring diameter ≥18mm and ≤29mm (cardiac CT measurement); * The diameter of the ascending aorta of the patient was \< 50mm. Exclusion Criteria: * Patients with bacteremia or toxemia; * previous history or active endocarditis; * Acute myocardial infarction (Q-wave MI, or non-Q-wave MI with increased creatine kinase isoenzyme and/or troponin T) within 30 days; * Echocardiography found any intracardiac mass, left ventricle or atrial thrombosis, vegetations; * Symptomatic atrial fibrillation that cannot be improved by medication; * Familial hypertrophic cardiomyopathy; * Mitral valve and tricuspid valve insufficiency (reflux Ⅱ level above); * Prior aortic valve grafts (mechanical or biological valve stents); * Known allergy to contrast agent, aspirin, heparin, ticlopidine, nickel-titanium memory alloy, or bovine products; * Known to be contraindication or allergic to all anticoagulant regimens, or unable to use anticoagulant during the test; * Other serious diseases that may reduce life expectancy to less than 12 months (e.g. clinically recurrent or metastatic cancer, congestive heart failure, etc.) * Current drug abuse problem (e.g., alcohol, cocaine, heroin, etc.); Plan to undergo surgery that may cause nonadherence to protocol or confusion in data interpretation. * Cerebrovascular accident (CVA) in the past 6 months; * Patients with common or internal carotid or vertebral artery stenosis (\> 70%); * WBC count \< 3×109/L, platelet count \< 50×109/ L; * Hemoglobin \< 90g/L; * Patients with severe coagulation dysfunction; * Severe left ventricular dysfunction, left ventricular ejection fraction \< 20%; * Abdominal or thoracic aortic aneurysm; * Hepatic encephalopathy or acute active hepatitis; * Receiving dialysis or a baseline creatinine level of \> 3.0 mg/dL (266μmol/L); * Have bleeding tendency or history of coagulation disease or refuse blood transfusion; * Have active gastric ulcer or active gastrointestinal (GI) bleeding; * Suffer from neurological diseases that seriously affect the ability to move or live in daily life; * People with mental illness or mental disorder who cannot express themselves normally; * Need emergency surgery for any reason; * Screening participants who had participated in other drug or medical device clinical trials within the previous 3 months; * Other conditions considered by the investigator to be inappropriate for participation in this clinical trial.