Objective To investigate the change characteristics of brain natriuretic peptide(BNP) after offpump coronary artery bypass grafting (OPCAB), and observe the relationship of BNP with atrial fibrillation, intensive care unit(ICU) stay time, time of withdrawing trachea tube, and usage of intraaortic balloon pump(IABP). Methods We retrospectively analyzed the clinical data of 168 consecutive patients with coronary artery diseases who underwent OPCAB in Beijing Anzhen Hospital from September 2009 to March 2010. There were 133 males and 35 females with an age of 60.77±9.32 years. BNP was determined before operation, on the operative day just after operation, and day 1, 2 and 3 after operation. At the same time, the relationship between BNP and ICU stay time, time of withdrawing trachea tube, occurrence of atrial fibrillation, and usage of IABP were also recorded. Results There were two inhospital deaths, due to low cardiac output syndrome, infection and circulatory failure respectively. BNP increased significantly after operation with the peak level occurring 1 day after operation, after which it decreased gradually. BNP level in patients with their left ventricular ejection fraction(LVEF) under 50% was significantly higher than that in patients with LVEF equal to or above 50% before and after operation(the median BNP level at the second postoperative day: 2 198.20 pg/ml vs. 531.65 pg/ml, Plt;0.05). BNP in patients using IABP was significantly higher than that in patients without using IABP before and after operation(the median BNP level at the first postoperative day: 5 066.75 pg/ml vs. 745.20 pg/ml, Plt;0.05). The ROC value was 0.834 when perioperative BNP was used to predict the possibility of using IABP. BNP in patients with postoperative atrial fibrillation was also significantly higher than that in patients without atrial fibrillation(the median BNP level at the first postoperative day: 1 070.60 pg/ml vs. 747.80 pg/ml, Plt;0.05). BNP was positively correlated with using IABP(at the third postoperative day: r=0.437, Plt;0.05), prognosis(at the first postoperative day:r=0.224, Plt;0.05), time of withdrawing trachea tube(at the third postoperative day: r=0.440, Plt;0.05), ICU stay time(at the third postoperative day: r=0.477, Plt;0.05). Conclusion BNP can be considered as one of the diagnostic criteria for ventricular dysfunction, and preoperative high BNP level is a risk factor for using IABP and ICU stay time equal to or longer than 3 days.