Objective To investigate the common sites and risk factom of reoperation for bleeding after coronary artery bypass grafts(CABG).Methods During Jan 2000 to July 2011,2765 CABG procedures hed been done in our hospital,including 874 cases with CABG by cardiopulmonary bypass,1891 cases with off-pump coronary artery bypass grafts (OPCAB),105 cases combined with other procedures (cardiac valve operation,resection of ventricular aneurysm,et al),216 cases applied intra-aortic balloon pump (LABP)).67 patients needed reoperation for bleeding,the morbidity is 2.4％.Factors that might affect the result of reoperation were analyzed by single-factor analysis.Results The following factors were related to high rates of reoperation (P ＜ 0.05 ):the internal mammary artery (IMA) used,anfithrombotic medication discontinued less 5 days before elective surgery,concurrent hypertension,combined with other surgery procedures and ages ＞70 years.It was not signifieantly related to CABG or OPCAB,ff use of IABP,ff concurrent diabetes,number of grafts inserted.Major sources of bleeding found in 48 patients were the IMA and its vessels bed,vein grafts,sternum,aortic faucet,midriff,thymus glrard bed vessels.Conclusion Prepared satisfactorily before operation,avoid risk factors can reduce reoperation for bleeding,but the most important is the operation carefully during operation of hemostasis.