A 68-years-old male with diabetes mellitius (HbA1c 6.5%) was referred for coronary artery bypass grafting(CABG). Preoperative coronary angiography (CAG) signed 3-vessels coronary disease[#2 75 %,#4 posterior descending (PD) 75%,#6 90%,#14 90%]. Minimally invasive coronary artery grafting (MICS CABG) was selected because of faster postoperative recovery than off-pump CABG via a 10 cm left 5th thoracotomy approach. In situ bilateral internal thoracic artery(BITA) and saphenous vein (SVG) was harvested by special manner using long type Harmonic. Bypass graft design was in situ right internal thoracic artery-LAD, in situ left internal thoracic artery-left circumtlex#14, and aorta-SVG-#4PD-#4atrio-ventricular. BITA, the ascending aorta for proximal anastomoses, and all coronary targets were directly accessed with off-pump technique. Heartstring III Proximal Seal System was used to anastomose SVG to the ascending aorta. There were no major postoperative complications. Postoperative CAG revealed all grafts patent and postoperative hospital stay was 14 days. This case was the 1st usage of Heartstring III Proximal Seal System in our clinic. We believe that the usage of Heartstring III Proximal Seal System in MICS CABG is realistically possible, and providing good quality;however, further research will be needed.