Aim To study the effect of tanshinone ⅡA on the vein graft stenosis after off-pumb coronary artery bypass grafting （OPCAB）. Methods Sixty patients undergoing OPCAB from 2006 to 2010 were randomly divided into two groups treated with tanshinone ⅡA （30 patients） or without tanshinone ⅡA （30 patients）. The vein graft stenosis was observed by CTA of heart after three years. Results The vein graft stenosis in the tanshinone ⅡA group was decreased as compared with the control group （P<0.05）. Conclusion Long term application of tanshinone Ⅱ A can alleviate the vein graft stenosis after OPCAB.