This article reports a case of a 70-year-old female patient who developed bioprosthetic mitral valve deterioration 4 months after her initial valve replacement surgery, manifesting as severe regurgitation and New York Heart Association Class Ⅲ. Due to the high risk of a redo open-heart surgery, she underwent a transapical transcatheter mitral valve-in-valve procedure. Intraoperatively, a J-Valve prosthesis was successfully implanted under echocardiographic and fluoroscopic guidance. Immediate transesophageal echocardiography confirmed an optimal valve position, complete resolution of regurgitation, and no significant paravalvular leak or left ventricular outflow tract obstruction. The patient's postoperative course was uneventful. She was extubated 16 hours post-procedure with significant improvement in cardiac function. Follow-up echocardiography showed normal prosthetic valve function.