Objective:To investigate the correlation between perioperative new onset atrial fibrillation and the prognosis of colorectal cancer.Methods:This study involved 180 colorectal cancer patients undgoing radical resection at the Department of Gastrointestinal Surgery, Longyan First Hospital from Jan 2014 to Jan 2015. Among them, 47cases suffered from perioperative new onset atrial fibrillation.Results:The perioperative new onset atrial fibrillation group had a higher mean age and a higher mean postoperative C-reactive protein level than the control group ( t=-3.080, P=0.002; t=-2.184, P=0.030). Hence these patients had a longer hospital stay ( t=-5.072, P=0.001; t=-2.577, P=0.011). Multivariate analysis showed that postoperative new onset atrial fibrillation, high postoperative mean C-reactive protein level, poor tumor differenciation and late tumor stage were independent risk factors for the prognosis of colorectal cancer ( HR=1.835, P=0.018; HR=1.008 P=0.017; HR=1.950 P=0.046; HR=1.300, P=0.047). The median survival time of perioperative new onset atrial fibrillation group and control group were 59.05 months and 63.23 months, respectively ( P=0.005). Conclusions:Colorectal cancer patients suffering from perioperative new onset atrial fibrillation were more common among advanced age and high postoperative mean C-reactive protein level with higher all-cause mortality.