BACKGROUND: With the expanded utilization of transcatheter aortic valve implantation (TAVI) to younger and lower surgical risk patients with severe aortic stenosis (AS), optimal medical therapy after TAVI procedure has become the main concern. Renin-angiotensin system inhibitors (RASi) are widely utilized in the area of cardiovascular disease including heart failure and myocardial infarction and revealed the ability to reverse left ventricular (LV) remodeling. Interests have, thus, been drawn in investigating whether the prescription of RASi after the TAVI procedure can prevent or reverse cardiac remodeling and improve long-term clinical outcomes. No recommendation regarding the prescription of RASi after TAVI is proposed yet due to the lack of evidence from randomized controlled trials, especially in the Chinese population. We, therefore, designed this randomized controlled trial to explore the effect of adding fosinopril to standard care in patients who underwent a successful TAVI procedure on the LV remodeling. METHODS: A total of 200 post-TAVI patients from seven academic hospitals across China will be recruited and randomized with a ratio of 1:1 to receive standard care or standard care plus fosinopril. Follow-up visits will take place at 30 days, 3 months, 6 months, 12 months, and 24 months from randomization to assess the clinical symptoms, any adverse events, cardiac function, and quality of life. Cardiac magnetic resonance will be performed at baseline and repeated at the 24-month follow-up visit to assess LV remodeling. DISCUSSION: This study will provide evidence regarding medical therapy for AS patients who underwent TAVI and filling the gap in the Chinese population. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2100042266 . Registered on 17 January 2021.