The main objective is to assess the effectiveness and safety of the MitralStitch repair system in patients with moderate to severe and severe mitral regurgitation.

Inclusion Criteria:

1. The age of patient is ≥18yrs;
2. Severe mitral regurgitation patients (The area of central regurgitation exceeds 40% of left atrial area or holosystolic eccentric regurgitation; VC≥0.07cm；regurgitant volume ≥60ml；RF ≥50%; EROA≥0.4cm2 (Satisfy any condition).
3. LVESD≤60mm, LVEF≥25%, small incision surgery of chest can be tolerated.
4. The subject was informed of the clinical application nature of the new technology and agreed to participate in all requirements of the clinical application of the new technology, signed the ICF and agreed to complete the follow-up and the inspection required during the follow-up period.

Exclusion Criteria:

1. Subject who are pregnant, lactating or scheduled to pregnant during the period of the clinical new technology.
2. Subjects with active endocarditis or rheumatic mitral valve disease.
3. Life expectancy <1 year for cardiac or other malignant tumors.
4. Participate in other clinical trial
5. In the judgment of the investigator, subjects had poor acceptance of chemotherapy, and they cannot complete the trial as required.