Objective    To analyze the effect of loop-in-loop technique and annuloplasty ring for the treatment of mitral valve prolapse (MVP) under total thoracoscopy. Methods    Between May 2012 and May 2017, 21 patients with MVP underwent mitral valve repair in our hospital. There were 12 males and 9 females with a mean age of 50.90±9.66 years and the mean weight of 64.81±11.56 kg. Loop-in-loop artificial chordae tendonae reconstruction and mitral annuloplasty were performed through the right atrial-atrial septal incision under total thoracoscopy. The water test and transesophageal echocardiography were performed during the operation to evaluate the effect of mitral annuloplasty. Data of echocardiography and chest radiography were collected postoperatively one week, before discharge and after discharge. Results    All the operations were successful without re-valvupoplasty or valve replacement, conversion to median thoracotomy, malignant arrhythmia, perioperative death or wound infection. Among them, 10 patients underwent tricuspid valvuloplasty, 1 patient underwent tricuspid valvuloplasty plus radiofrequency ablation simultaneously. The mean cardiopulmonary bypass time was 255.57±37.24 minutes, aortic occlusion time was 162.24±19.61 minutes, the number of loop was 2–5 (3.29±0.78), the size of ring was 28–34 (31.11±1.88) mm, ventilator assistance time was 19.43±14.68 hours, ICU time was 58.45±24.60 hours and postoperative hospital stay was 12.28±3.61 days. Transthoracic echocardiography was re-examined postoperatively. Mild-mitral regurgitation was found in 3 patients. Warfarin anticoagulant therapy was given orally for 6 months postoperatively. The patients were followed up regularly for 2–51 months at 1, 3, 6 and 12 months postoperatively. Left ventricular end-diastolic diameter (LVEDD) was 45.06±2.96 mm, left ventricular end-diastolic volume 108.11±17.09 mL, left atrial diameter (LAD) 35.56±6.93 mm and cardiothoracic ratio 0.53±0.13 at discharge which were significantly smaller than those at admission (P<0.05). Pulmonary artery pressure was 19.22±6.38 mm Hg which was significantly lower than that at admission (P<0.05), but left ventricular ejection fraction (62.33%±4.00%) had no significant change (P>0.05). The LAD and LVEDD were significantly smaller than those before operation, and the cardiac function improved to some extent during the follow-up. No new mitral valve prolapse, increased regurgitation, infective endocarditis, thromboembolism or anticoagulation-related complications were found during the follow-up. Conclusion    Loop-in-loop artificial chordae tendon implantation combined with mitral annuloplasty is a safe and effective method for MVP under total thoracoscopy with minimal trauma, satisfactory cosmetic effect, and good early- and medium-term results. It is worth of popularizing. However, the operation time needs to be further shortened, and its long-term clinical effect needs further follow-up and other researches to confirm.