Objective:To explore the evaluation of transesophageal echocardiography(TEE) in patients with massive regurgitation of posterior mitral valve prolapse undergoing transapical off-pump NeoChord repair.Methods:Eight patients from April to July 2019 in the Second Affilliated Hospital of Zhejiang Univerity with massive regurgitation of posterior mitral valve prolapse underwent NeoChord repair mitral valve morphology, prolapse position and regurgitation degree were evaluated before NeoChord implantation by TEE. Under TEE guidance, the puncture site was identificated, the position and length of artificial chordae were adjusted during implantation. NeoChord′s function and positon after implantation were observed. The complications were monitored during the operation.Results:Mitral valve repair by NeoChord system was successfully performed with implantation of 2 to 4 artificial chordaes in eight patients respectively. Intraoperative TEE and pre-discharge transthoracic echocardiography(TTE) showed moderate MR in two patients, mild to moderate MR in one patient, mild MR in the remaining five patients. Reexaminations with TTE at 1 month after operation showed moderate MR in six patients, and mild to moderate MR in two patients. And no postoperative complications were noted.Conclusions:NeoChord system is a safe, effective and feasible treatment method for patient with mitral valve prolapse, TEE plays an important role during NeoChord implantation.